INORGANIC Part 1
Historical Introduction page sub-index: 1.1 The
early classification of Antoine Lavoisier of 1789 * 1.2 The 1829 work of
Johann Döbereiner *
1.3 The work of John
Newlands 1864 * 1.4 Dmitri Mendeleev's
Periodic Table and Lothar-Meyer graphs of ~1869 * 1.5 A modern Periodic Table based on the electronic structure of
atoms * 1.6 Where did the elements come from
originally and where do we get the elements from today?
Advanced
Level Inorganic Chemistry Periodic Table Index *
Part 1
Periodic Table history
* Part 2
Electron configurations, spectroscopy,
hydrogen spectrum,
ionisation energies *
Part 3
Period 1 survey H to He *
Part 4
Period 2 survey Li to Ne * Part
5 Period 3 survey Na to Ar *
Part 6
Period 4 survey K to Kr and important trends
down a group *
Part 7
s-block Groups 1/2 Alkali Metals/Alkaline Earth Metals *
Part 8
p-block Groups 3/13 to 0/18 *
Part 9
Group 7/17 The Halogens *
Part 10
3d block elements & Transition Metal Series
*
Part 11
Group & Series data & periodicity plots * All
11 Parts have
their own sub-indexes near the top of the pages
1. A
few snippets of the past and continuing history
of the Periodic Table
Not all
scientists are mentioned who perhaps should be, but I've tried to pick
out a few 'highlight' and added some footnotes on what was happening in
terms of the development of the detailed knowledge of the structure of
atoms, so essential to the modern interpretation of the Periodic Table.
Its a good 'advanced' example of how science works i.e. the relationship
between experimental data and theories to account for it, questions
posed, questions answered, leading to more comprehensive and accurate
theories developing.
1.1 The
early classification of Antoine Lavoisier of 1789
Antoine
Lavoisier's 1789 classification of substances into four
'element' groups
|
acid-making elements |
gas-like
elements |
metallic
elements |
earthy
elements |
sulphur |
light |
cobalt,
mercury, tin |
lime
(calcium oxide) |
phosphorus |
caloric
(heat) |
copper,
nickel, iron, |
magnesia
(magnesium oxide) |
charcoal
(carbon) |
oxygen |
gold,
lead, silver, zinc |
barytes
(barium sulphate) |
|
azote
(nitrogen) |
manganese,
tungsten |
argilla
(aluminium oxide) |
|
hydrogen |
platina
(platinum) |
silex
(silicon dioxide) |
- The understanding that an
element as a unique atomic 'building block' which could not be split
into simpler substances and compound is a chemical combination of
two or more elements were not at all understood at the time of
Lavoisier.
-
'light' and
'caloric' (heat), were considered 'substances' and the last
'scientific' vestige of the elements of 'earth, fire, air and water'
which had there conceptual origin in the Greek civilisation of
2300-2800 years ago.
-
However,
Lavoisier was correct on a few things e.g. the elements sulphur,
phosphorus and carbon and correctly described their oxides as acidic
e.g. dissolved in water turned litmus turns red.
-
Many metallic
elements, were correctly identified though I doubt if they were pure
though!
-
What he
described as the 'earthy elements' are of course compounds, a
chemical combination of a metal plus oxygen or sulfur (both O and S in case
of barium).
-
He didn't have
very high temperature smelting technology, or a reactive metal from
electrolysis (came in about 1806 onwards)' to 'separate' the
elements in some way e.g. he couldn't extract a reactive metal! In
other words, at this time, the wrong 'classification' was due to a
lack of chemical technology as much as lack of knowledge.
-
Atomic
structure history note: You can see from the 1789 'table'
Lavoisier and his contemporaries did not have the experiment
techniques, data or theoretical framework to clearly distinguish
between 'elements' and 'compounds'. It was only in 1808 Dalton
proposed his atomic theory based on experimental data and produced
the first list of 'atomic weights', which we now call relative
atomic masses.
1.2 The 1829 work of
Johann Döbereiner
-
Johann
Döbereiner noted that certain elements seemed to occur as
'triads' of similar elements e.g.
-
(i)
lithium, sodium and potassium
-
(ii)
calcium, strontium and barium
-
(iii)
chlorine, bromine and iodine
|
-
Döbereiner
was amongst the first scientists to recognise the 'group'
idea of chemically very similar elements.
-
Three groups he
'recognised' were (i) Group 1
Alkali Metals, (ii) Group 2 Alkaline Earth Metals, (iii) Group 7
Halogens.
-
Atomic structure
history note: The physical and chemical likeness of the three
members of these 'triad groups' should be evident and it was based
purely on observation, however Döbereiner and contemporaries where
unaware of the atomic and molecular nature of these elements e.g. the
atomic nature of the metals (M atoms) and the molecular nature of the
Halogens (X2 diatomic molecules). In fact the concept of a
'molecule' was first realised by Avogadro in 1811 but it took 50 years
before the genius of his experimental work and intuition was fully
realised.
1.3 The work of John
Newlands 1864
Newland's 'Law
of
Octaves' (his 'Periodic Table' of 1864)
|
H |
Li |
Ga |
B |
C |
N |
O |
F |
Na |
Mg |
Al |
Si |
P |
S |
Cl |
K |
Ca |
Cr |
Ti |
Mn |
Fe |
Co,
Ni |
Cu |
Zn |
Y |
In |
As |
Se |
Br |
Rb |
Sr |
Ce,
La |
Zr |
Di,
Mo |
Ro,
Ru |
Pd |
Ag |
Cd |
U |
Sn |
Sb |
Te |
I |
Cs |
Ba,
V |
Ta |
W |
Nb |
Au |
Pt,
Ir |
Tl |
Pb |
Th |
Hg |
Bi |
Cs |
-
Newlands
recognised that every 7 elements, the 8th seemed to be very similar
to the 1st of the previous 7 when laid out in a 'periodic' manner
and he was one of the first scientists to derive a 'Periodic Table'
from the available knowledge.
-
e.g. his 'table'
consists of almost
completely genuine elements (Di was a mix of two elements), classified
roughly into groups of similar elements and a real recognition of
'periodicity'
-
He also recognised that the 'groups' had more
than 3 elements (not just 'triads'), and was correct to mix up metals and non-metals in same group
e.g. in 5th column there is carbon, silicon, tin (Sn) from what we
know call Group 4. However, indium is in group 3 but Ti, Zr have a
valency of 4, like Group 4 elements and do form part of vertical
column in what we know call the Transition Metal series
-
Other correct
'patterns' if not precise are recognisable in terms of the modern
Periodic Table e.g. half of column 2 is Group 1, half of column 3 is
Group 2, half of column 5 is Group 4, half of column 6 is Group 5,
half of column 7 is Group 6. If we put his column 1 as column 7, it
would seem a better match of today!
-
Although none of his
vertical column groups match completely but the basic
pattern of the modern periodic table was emerging. However column's 1 and 7 do seem particularly
mixed up compared to the modern periodic table.
-
However, he was very
much on the right track and deserves more credit than he is often given
because he was a pioneer in the idea of setting out the elements to
give vertical columns of 'like
elements', which we now call 'groups', and you see this in the contents of
most of the columns.
Atomic
structure history note: A good wedge of history at this point!
-
The
Greeks
Leucippus and Democritus ~500-400 BC wondered what was the result of
continually dividing a substance i.e. what was the end product or smallest
bit i.e. what was left that was indivisible - the word atom/atomic
is from Greek adjective atomos meaning 'not divisible'.
-
They considered that matter is made of
atoms that are too small to be see and cannot be divided into
smaller particles. They speculated that there was empty space
between solid atoms and that atoms were the same throughout a cross
section and atoms could have different sizes, shapes and masses.
-
These were brilliant ideas for their
time and such concepts were the result of excellent intuitive
thinking BUT the famous and much more eminent and revered
philosopher Aristotle, didn't think much of their theory, and so
atomic theory never developed for nearly 2000 years!
-
Its worth commenting further on the
Greeks. Although brilliant in intellectual discourse on many
subjects and legendary mathematicians, they were NOT very good at
science. Most Greek intellectuals did not consider doing experiments
to test out theories as very important, and therefore over 2000
years ago they actually rejected the principal methods by which we
today practice science!
-
However, the Greeks idea of atoms was not
completely forgotten and
later revived by Boyle and Newton but with little progress.
-
But,
in 1808, Dalton
(1766-1844)
proposed his
atomic theory
that all matter was made up of substances of some kind of 'atomic
nature' and
the different types of atoms (elements) combined together to give
all the different substances of the physical world.
-
His theory included the idea that
atoms in an element are all the same and an element was not
divisible into more fundamental substances.
-
In 1808 there was no actual proof that
individual atom particles existed but Dalton envisaged an
element as a fundamental type of substance that could not be
split into simpler substances.
-
Dalton considered that a compound is
made by joining at least two different elements together to form
a new substance in specific proportions (we now write as a
formula, and atoms do not change themselves
in a reaction but from the original reactants they re-arrange to
form the products.
-
He also produced
the first list of 'atomic weights' (we now call relative atomic
masses) on a scale based on hydrogen which was given the arbitrary value of
1 since it was lightest element
known, and, as it happens, correctly so.
-
Dalton also devised symbols for the
different elements, but his 'picturesque' symbols were not
universally adopted and today's elements letter symbols were
introduced and promoted by the chemist Jons Berzelius in 1811.
-
In 1876 Goldstein
and Jean Perrin in 1895 passed a high-voltage
electrical discharge through various gases and discovered beams of
negatively charge particles where formed.
-
They where called cathode
rays and, where in fact, what we now know as negative electrons (but
they didn't know this!).
-
The electrons were
emanating from the negative electrode and being accelerated towards
the positive anode.
-
They were unaware that positive ions were also
produced and beamed in the opposite direction.
-
Up till then, it was
just assumed that matter consisted of Daltons 'atoms' i.e. particles
that could not be broken down into smaller particles, so did not have any
meaningful structure but just combined in various ways to
make different compounds.
-
This was the real start
of research into 'atomic structure', especially as it was soon found
later on that a stream of positive particles was travelling in the
opposite direction to the 'negative electrons'!
-
Goldstein's and Perrin's
experiments also provided the experimental basis for the development
of the mass spectrograph by Aston - what we know now as a mass
spectrometer.
Background developments in
identifying metallic elements
Before proceeding further it is
pertinent to consider the history of metal extraction, since most
elements in the periodic table are metals and the more elements known,
the more the structure of the periodic table can emerge. The ease of
extraction and ultimately being identified as an element is intimately
connected to how easy it is to extract a metal. A short summary, based
on the reactivity series of metals
and methods of extracting metals
from ores is outlined below.
1.4 Dmitri Mendeleev's
Periodic Table and Lothar Meyer's Graphs of 1869
-
Mendeleev (Russian
chemist) first published his 'Periodic Table' work
simultaneously in 1869 with the work of Lothar Meyer (German chemist) who looked at the
physical properties of all known elements.
-
Lothar Meyer noted 'periodic' trend
patterns e.g. peaks and troughs when melting or boiling points, specific
heat and atomic volume values were plotted against 'atomic weight' - what we now call
relative atomic mass.
-
My modern versions of
Lothar Meyer's graphs are shown on a separate pages, plus others and now the properties are
plotted against atomic/proton number and I've managed to collect
most data up to element 96.
-
Elements
Z = 1 to 20 covering Periods 1-3 and start of Period 4
Elements Z = 1 to 38
covering Periods 1-4 and start of Period 5
Elements
Z = 1 to 96 covering Periods 1-6 and start of Period
7
-
The atomic volume graph
is shown below clearly showing the 'periodic' highest volumes for
the alkali metals - the least dense of the elements in liquid or
solid form.

My modern version of
Lothar-Meyer's 'atomic volume' curve
and below one of Mendeleev's
early versions of the Periodic Table

-
Mendeleev
laid out all the known elements in order of
'atomic weight' (what we know call relative atomic mass, Ar) except for
several examples like tellurium (Te, Ar = 127.60) and iodine (I,
Ar = 126.90) whose order he
reversed because chemically they seemed to be in the wrong vertical
column! Smart thinking!
-
Argon (Ar, Ar
= 39.95) and potassium (K, Ar = 39.10) is the 2nd example,
but that was not a problem for chemists at the time, because the Group 0
Noble Gases hadn't been discovered by then!
-
These 'anomalies' in
the order of 'atomic weights' are explained by the existence of isotopes
which were discovered ~1916 and the neutron finally characterised in
1932.
-
Isotopes of elements
are atoms of the same proton number with different numbers of neutrons,
hence atoms of the same element with different mass numbers.
-
The most abundant
stable isotope of potassium is 39K, and that of argon is 40Ar, hence the anomaly.
-
Naturally occurring
iodine is 100% 127I, but tellurium has a range of isotopic
masses from 120Te to 130Te but more the heavier
isotopes are more abundant than the lighter isotopes.
-
By 1869, Mendeleev
and Lothar Meyer had an advantage over Newlands (1864) because by
then there was an
increased
number of known elements and hence 'groups' of similar elements were becoming more clearly defined.
-
Mendeleev used a double column
approach which is NOT incorrect, i.e. a sort of group xA and xB
classification. This is due to the 'insert' of transition metals,
some of whom show chemical similarities to the vertical 'groups'.
 |
 |
This is
how Mendeleev's periodic table looked in an early Russian
publication (in Russian). The left image doesn't look quite as familiar,
BUT, if you rotate it round 90o it begins to look
much more familiar! All 'familiar 7 vertical groups (1-7,
also now numbered 1-2 and 13-17) show up, remember Noble
Gases had not been discovered yet. I've added comments that
partially explain why Mendeleev got some of the groupings
wrong in terms of our modern groups 1 to 7 of the periodic
table. Note that despite it being in Russian from the late
19th century, most of the chemical symbols should be
familiar to you! that's the idea - a universal language! Group 1 is correct bar Tl
and radioactive francium was unknown. Thallium is (Tl) is in
group 3 but does have a valency of 1.
Group 2 is partly correct, but two
wrong, Zn and Cd, but the latter two d block elements have a
valency of 2 just like Be and Mg
Group 3 B and Al 'correct' but
included an unknown and U & Y, the latter two (but have a
valency of 3).
Group 4 three correct and one unknown
predicted (Ge) and lead (Pb) in the wrong place, but the
principal valency of lead is 2 so it was included with the
group 2 metals Ca, Sr and Ba (Mg is missing?).
Group 5 is all correct, quite
remarkable since you go down the group from non-metals to a
metal.
Group 6 is all correct, again quite
remarkable grouping, only the unknown radioactive element
polonium is missing.
Group 7 is all correct, brilliant
again, but couldn't have known about radioactive
astatine at that time.
Although the complications due to the
transition metal series and lanthanide and actinide series
of metals due to the electronic sub-groups we now recognise
as d blocks or f blocks, Mendeleev still recognised some as
'blocks of ' metals with some similarity.
So, no wonder he is given great
historical credit for his insight and foresight into the
development of the Periodic Table. |
1.5
A modern
version Periodic Table based on the electronic structure of
atoms
The electronic basis of the periodic table is
explained in Part 2.
Pd |
s–block
metals |
3d to 6d blocks including the Transition Metals (Periods 4
to 7), note that the 1st (d1) and 10th (d10)
block metals are NOT true
transition elements. So 8/10 of 3d blocks are true transition
metals d2 to d9 elements. |
p–block
metals and non-metals |
Gp1 |
Gp2 |
Gp3/*13 |
Gp4/*14 |
Gp5/*15 |
Gp6/*16 |
Gp7/*17 |
Gp0/*18 |
1 |
1H Note: (i) H does not readily
fit into any group, (ii) He not strictly a 'p' element but does
belong in Gp
0/18
|
2He |
2 |
3Li |
4Be |
Full IUPAC modern Periodic Table of Elements
ZSymbol, z = atomic or proton
number |
5B |
6C |
7N |
8O |
9F |
10Ne |
3 |
11Na |
12Mg |
*Gp3 |
*Gp4 |
*Gp5 |
*Gp6 |
*Gp7 |
*Gp8 |
*Gp9 |
*Gp10 |
*Gp11 |
*Gp12 |
13Al |
14Si |
15P |
16S |
17Cl |
18Ar |
4 |
19K |
20Ca |
21Sc |
22Ti |
23V |
24Cr |
25Mn |
26Fe |
27Co |
28Ni |
29Cu |
30Zn |
31Ga |
32Ge |
33As |
34Se |
35Br |
36Kr |
5 |
37Rb |
38Sr |
39Y |
40Zr |
41Nb |
42Mo |
43Tc |
44Ru |
45Rh |
46Pd |
47Ag |
48Cd |
49In |
50Sn |
51Sb |
52Te |
53I |
54Xe |
6 |
55Cs |
56Ba |
*57-71 |
72Hf |
73Ta |
74W |
75Re |
76Os |
77Ir |
78Pt |
79Au |
80Hg |
81Tl |
82Pb |
83Bi |
84Po |
85At |
86Rn |
7 |
87Fr |
88Ra |
*89-103 |
104Rf |
105Db |
106Sg |
107Bh |
108Hs |
109Mt |
110Ds |
111Rg |
112Cn |
113Nh |
114Fl |
115Mc |
116Lv |
117Ts |
118Og |
Group
1 Alkali Metals
Group 2 Alkaline Earth Metals
Group 7/17 Halogens
Group 0/18 Noble Gases
Take note of the four
points on the right |
|
*57La |
58Ce |
59Pr |
60Nd |
61Pm |
62Sm |
63Eu |
64Gd |
65Tb |
66Dy |
67Ho |
68Er |
69Tm |
70Yb |
71Lu |
|
*89Ac |
90Th |
91Pa |
92U |
93Np |
94Pu |
95Am |
96Cm |
97Bk |
98Cf |
99Es |
100Fm |
101Md |
102No |
103Lr |
*Horizontal insert in Period 6 of
Lanthanide
Metal Series (Lanthanoids) Z=57 to 71
includes 4f–block
series (elements 58–71). Element 57 is the start of the 5d
block, interrupted by the 14 4f block elements and then
continues with elements 72-80.
*Horizontal insert
in Period 7 of the Actinide Series of Metals (Actinoids) Z=89–103
including the 5f–block
series (elements 90–103). Element 57 is the start of the 5d
block, interrupted by the 15 5f block elements and continues
with elements 72-80. |
-
Using 0 to
denote the Group number of the Noble Gases is historic i.e. when its valency was
considered zero since no compounds were known. However, from
1961 stable compounds of
xenon have been synthesised exhibiting up to the maximum possible expected valency of 8
e.g. in XeO4.
-
* 21Sc to 30Zn can be considered
as the top elements in the vertical Groups 3 to 12 (marked
as *Gp3 to *Gp12).
-
*Therefore
Groups 3–7 and 0 can also be numbered as
Groups 13 to 18 (marked as
*13,
*14,
*15,
*16,
*17 and
*18) to fit in with the maximum number of vertical columns of elements
in periods 4 and 5 (18 elements per period).
-
I'm afraid
this can make things confusing, but there
it is, classification is still in progress and the notation Group 1 to 18
seems due to become universal.
-
Elements up to Z = 118 have
now been synthesised, if only a few atoms have been identified !
|
-
With increasing knowledge
of the elements of the Periodic Table it is now laid out in order of
atomic (proton) number.
-
Due to
isotopic masses, the relative atomic mass does go 'up/down' occasionally
(there is no obvious 'nuclear' rule that accounts for this, at least
at GCSE/GCE level!). BUT chemically Te
is like S and Se etc. and I is like Cl and Br etc. and so are placed
in their correct 'chemically similar family' group and this is now backed up by
modern knowledge of the electron structure
of atoms.
-
We now know the electronic structure of elements and can
understand sub-levels and the 'rules' in electron structure e.g. 2 in
shell 1 (period 1, 2 elements H to He), 8 in shell 2 (period 2, 8
elements Li to Ne), there is a sub-level which allows an extra 10
elements (the transition metals) in period 4 (18 elements, K to Kr).
this also explains the sorting out of Mendeleev's A and B double
columns in a group. The
periods are complete now that we know about Noble Gases.
-
The use and
function of the Periodic Table will never cease! Newly 'man-made' elements
are being synthesised.
-
In the 1940's
Glenn Seaborg was part of a research team developing the materials
required to produce the first atomic bombs dropped on Hiroshima and
Nagasaki. He specialised in separating all the substances made in the
first nuclear reactors and helped discover the series of 'nuclear
synthesised' elements beyond the naturally occurring limit of uranium
(92U). From element 93 to 118 are now known, so the structure of the bottom part of the periodic
table will continue to grow. There is plenty of scope for present day, and
future Mendeleev's!!!! (will you be one of them!?).
-
Atomic structure
history note: From 1913 onwards the electron structure of atoms was
gradually being understood and paralleling the developing knowledge of
the structure of the nucleus and its importance in determining which
element an atom was i.e. the atomic/proton number.
The Bohr theory of the hydrogen spectrum
(see section 2.6) postulated that the electrons surrounding the
positive nucleus could only exist in specific energy levels and that any
electron level change must involve a specific input/output of energy -
the quanta e.g. a photon of light or X-rays etc.
-
In the 1920's and
1930's scientist-mathematicians like Heisenberg and Schrödinger were
developing the mathematical equations known as wave mechanics. These
mathematical theories describe the detailed behaviour of electrons, and
out of these equations come the four quantum numbers from which are
derived the set of rules we use to
assign electrons in their respective levels (see section 2.2),
which ultimately determines the chemistry of an element.
-
The 'many' names used to
indicate the various groups and series of elements in the periodic table
Alkali metals – The very reactive metals of group 1: Li, Na, K,
Rb, Cs, Fr
Alkaline earth metals – The metals of group 2: Be, Mg, Ca, Sr,
Ba, Ra
Pnictogens – The elements of group 5/15: N, P, As, Sb, Bi
(non-metals ==> metals)
Chalcogens – The elements of group 6/16: O, S, Se, Te, Po, Lv
(non-metals ==> metals)
Halogens – The elements of group 7/17: F, Cl, Br, I, At
Noble gases – The elements of group 0/18: He, Ne, Ar, Kr, Xe, Rn
Lanthanoids – Elements 57–71: La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb,
Dy, Ho, Er, Tm, Yb, Lu
Actinoids – Elements 89–103: Ac, Th, Pa, U, Np, Pu, Am, Cm, Bk,
Cf, Es, Fm, Md, No, Lr
Rare earth elements – Sc, Y, and the lanthanoids
Transition metals – Elements in groups 3 to 11 or 12. (eg 3d
block Sc to Cu or Zn)
Other miscellaneous 'names' comments, not standard IUPAC descriptors
Lanthanoids and actinoids may be referred to as lanthanides
and actinides respectively.
Post-transition metals – metals of groups 13–16: Al, Ga, In, Tl,
Sn, Pb, Bi, Po.
Metalloids – elements with properties intermediate between metals
and non-metals: B, Si, Ge, As, Sb, Te, At.
Diatomic nonmetals – nonmetals that exist as diatomic molecules
in their standard states: H, N, O, F, Cl, Br, I.
Superactinides – hypothetical series of elements 121 to 155,
which includes a predicted "g-block" of the periodic table.
Precious metal – non-radioactive metals of high economical value
eg silver, gold, platinum
Coinage metals – various metals used to mint coins eg the coinage
metals Ni, Cu, Ag, and Au.
Platinum group – Ru, Rh, Pd, Os, Ir, Pt
Noble metal – vague term for corrosion resistant metals like
silver and gold and the platinum-group metals
Heavy metals – metals like lead, on the basis of their density,
atomic number, or toxicity
Native metals – metals that can occur pure in nature eg gold and
copper
Transuranium elements – elements with atomic numbers greater than
92 (U)
Transactinide elements – elements after the actinides with atomic
numbers greater than 103 (Lr)
Transplutonium elements – elements with atomic number greater
than 94 (Pu)
1.6
Where did elements come from originally? Where do we
get the elements from?
(a) Where did elements come from
originally? It all starts in the STARS!
-
The ultimate origin of all elements
is the nuclear reactions that go on when stars are formed from
inter-stellar dust and gas forming a huge combined mass due to
gravity, and then 'chunks' of a star cool down to form planets. The
heaviest elements are formed in nuclear fusion reactions when stars
self-destruct in super-nova explosions.
-
The nuclear synthesis of light elements
up to Z = 26 (Fe, iron) occurs in stars formed from the condensation
of hydrogen and helium atoms.
-
Eventually, as the mass increases,
the force of gravity causes such compression that the temperatures
rise considerably at high matter densities and nuclear reactions
begin.
-
Up to Z = 26 nuclei, they are usually
formed energy releasing fusion processes or the decay of unstable
nuclei
-
There are hundreds of possible
nuclear transformations possible, so, below, I've chosen some examples of possible nuclear
reactions, whose products fit in with the isotopes, mass numbers,
relative atomic masses etc. which A level chemistry students are
likely to come across ...
-
... in the nuclear equations, for the
nuclide symbol AZX,
A = mass number, Z = atomic number, X = element
symbol
-
11H + 11H
==> 21H + 10n
-
21H + 11H
==> 32He + Ɣ
-
32He + 32He
==> 42He + 211H
-
From helium-3, the formation of
helium-4, the most common isotope of helium we find on earth.
-
From helium-4, by what is known as
the alpha process, a succession of heavier elements can be
synthesised in subsequent nuclear reactions ...
-
242He ==> 84Be
-
84Be + 42He
==> 126C
-
126C + 42He
==> 168O
-
168O + 42He
==> 2010Ne
-
2010Ne + 42He
==> 2412Mg
-
2410Mg + 42He
==> 2814Si
-
2814Si + 42He
==> 3216S
-
3216S + 42He
==> 3618Ar
-
3618Ar +
42He
==> 4020Ca
-

-
You can see from the Periodic Table
of relative atomic masses how the alpha-process ('helium burning'
has produced the values for C, O, Ne, Mg, Si, S, Ar and Ca from the
principal isotope of multiples of four mass units.
-
There are lots of other possibilities
involving H and He nuclei and particularly complicated nuclear
fusion cycle involving carbon nuclei e.g. the six step cycle ...
-
126C +
11H
==> 137N
-
137N
==> 13cC +
0+e
-
136C +
11H
==> 147N
-
147N +
11H
==> 158O
-
158O
==> 157N +
0+e (decay of oxygen-15 by positron
emission)
-
177N +
11H
==> 126C
+ 42He
-
You can also see how other isotopes
of an element can be formed and in the cycle carbon-12 is reformed
to continue these particular nucleosynthesis pathways.
-
There is a good analogy here with
auto-catalytic cycles in chemistry e.g.
the removal of ozone by chlorine atoms.
-
The heavier elements beyond iron i.e.
Z > 26 Co cobalt onwards must be formed by energy absorbing
processes including neutron capture e.g. the formation of technetium
from molybdenum
-
9842Mo +
10n ==> 9942Mo
-
9942Mo ==>
9943Tc + 0-e
-
Similarly, gallium can be formed from
zinc, i.e. again forming an element of higher atomic number ...
-
6830Zn +
10n ==> 6930Zn
followed by 6930Zn ==> 6931Ga
+ 0-e
-
So you can see that these nuclear
fusion, neutron or proton capture, nuclear decay etc., can over
time, gradually produce all the heavier elements up to element 92
uranium, the last of our naturally occurring elements.
-
Even though
small amounts of 23892U are eventually formed,
it requires the highest of temperature e.g. in a super-nova explosion of
giant stars a lot bigger than our sun!
-
Some examples of nuclear fusion
reactions to form heavier elements are quoted in
Part 3.4 Where do heavier elements come
from?
-
All
the elements from atomic numbers 1-92 (H-U) naturally occur on
Earth, though some are very unstable-radioactive and decay to form
more nuclear stable elements.
-
Many isotopes of
elements after lead, 82Pb are unstable.
-
After uranium, 92U,
the vast majority of the isotopes of
the elements of atomic number 93+ are inherently unstable.
-
They will not
have survived even if they were formed billions of years ago in the Sun,
and
retained or formed in the initial 'spin-off' material that formed the
'very early' Earth.
-
However, the
advent of nuclear reactors has enabled up to kg quantities of e.g.
plutonium, 94Pu (used in nuclear reactors and weapons) and americium,
95Am
(used in smoke alarms) to be produced.
-
Cyclotrons, particle bombardment linear accelerators, have enabled 'super-heavy'
elements up to Z = 118? to be 'synthesised', but only a few atoms at a
time (The Russia-US space race seems to have been partly replaced by 'who
can synthesize the biggest atom'!).
-
One things for certain, the
Periodic Table still keeps growing with newly synthesised elements!
(b)
Where, and how, do we get the elements from the
earth?
-
Everything around you is made up of
the elements of the periodic table, BUT most are chemically
combined with other elements in the form of many naturally
occurring compounds e.g.
-
hydrogen and oxygen in water,
sodium and chlorine in sodium chloride ('common salt'), iron,
oxygen and carbon as iron carbonate, carbon and oxygen as carbon
dioxide etc. etc.!
-
Therefore, most elements can only be
obtained by some kind of chemical process to separate or
extract an element from a compound e.g.
-
However some elements never occur
as compounds or they occur in their elemental form as well as
in compounds e.g.
-
The Group 0 Noble Gases are so
unreactive they are only present in the atmosphere as individual
atoms. Since air is a mixture, these gases are separated from
air by a physical method of separation by distillation of
liquified air. The elements oxygen and nitrogen are obtained
from air at the same time, which is far more convenient than
trying to get them from compounds like oxides and nitrates etc.
-
Gold/platinum is are the least
reactive metals and are usually found 'native' as the
yellow/silver elemental metal.
-
Relatively unreactive metals like
copper and silver can also be found in their elemental form in
mineral deposits as well as in metal ores containing compounds
like copper carbonate, copper sulphide and silver sulphide.
-
The non-metal sulphur is found
combined with oxygen and a metal in compounds known as
sulphates, but it can occur as relatively pure sulphur in yellow
mineral beds of the element.
-
-
APPENDIX 1. ALL THE
KNOWN ELEMENTS
Elements from Z = 1 to 118 in alphabetical order, so,
given the atomic number, find it on the full modern periodic table above
(section 1.5)
Chemical Symbol
|
Element name |
Atomic No. Z
|
Ac |
Actinium |
89 |
Al |
Aluminium/Aluminum |
13 |
Am |
Americium |
95 |
Sb |
Antimony |
51 |
Ar |
Argon |
18 |
As |
Arsenic |
33 |
At |
Astatine |
85 |
Ba |
Barium |
56 |
Bk |
Berkelium |
97 |
Be |
Beryllium |
4 |
Bi |
Bismuth |
83 |
Bh |
Bohrium |
107 |
B |
Boron |
5 |
Br |
Bromine |
35 |
Cd |
Cadmium |
48 |
Cs |
Caesium/Cesium |
55 |
Ca |
Calcium |
20 |
Cf |
Californium |
98 |
C |
Carbon |
6 |
Ce |
Cerium |
58 |
Cl |
Chlorine |
17 |
Cr |
Chromium |
24 |
Co |
Cobalt |
27 |
Cn |
Copernicium |
112 |
Cu |
Copper |
29 |
Cm |
Curium |
96 |
Ds |
Darmstadtium |
110 |
Db |
Dubnium |
105 |
Dy |
Dysprosium |
66 |
Es |
Einsteinium |
99 |
Er |
Erbium |
68 |
Eu |
Europium |
63 |
Fm |
Fermium |
100 |
Fl |
Flerovium |
114 |
F |
Fluorine |
9 |
Fr |
Francium |
87 |
Gd |
Gadolinium |
64 |
Ga |
Gallium |
31 |
Ge |
Germanium |
32 |
Au |
Gold |
79 |
Hf |
Hafnium |
72 |
Hs |
Hassium |
108 |
He |
Helium |
2 |
Ho |
Holmium |
67 |
H |
Hydrogen |
1 |
In |
Indium |
49 |
I |
Iodine |
53 |
Ir |
Iridium |
77 |
Fe |
Iron |
26 |
Kr |
Krypton |
36 |
La |
Lanthanum |
57 |
Lw |
Lawrencium |
103 |
Pb |
Lead |
82 |
Li |
Lithium |
3 |
Lv |
Livermorium |
116 |
Lu |
Lutetium |
71 |
Mg |
Magnesium |
12 |
Mn |
Manganese |
25 |
Mt |
Meitnerium |
109 |
Md |
Mendelevium |
101 |
Hg |
Mercury |
80 |
|
Chemical Symbol
|
Element name
|
Atomic No.
Z
|
Mo |
Molybdenum |
42 |
Mc |
Moscovium |
115 |
Nd |
Neodymium |
60 |
Ne |
Neon |
10 |
Np |
Neptunium |
93 |
Ni |
Nickel |
28 |
Nh |
Nihonium |
113 |
Nb |
Niobium |
41 |
N |
Nitrogen |
7 |
No |
Nobelium |
102 |
Og |
Oganesson |
118 |
Os |
Osmium |
76 |
O |
Oxygen |
8 |
Pd |
Palladium |
46 |
P |
Phosphorus |
15 |
Pt |
Platinum |
78 |
Pu |
Plutonium |
94 |
Po |
Polonium |
84 |
K |
Potassium |
19 |
Pr |
Praseodymium |
59 |
Pm |
Promethium |
61 |
Pa |
Protactinium |
91 |
Ra |
Radium |
88 |
Rn |
Radon |
86 |
Re |
Rhenium |
75 |
Rh |
Rhodium |
45 |
Rg |
Roentgenium |
111 |
Rb |
Rubidium |
37 |
Ru |
Ruthenium |
44 |
Rf |
Rutherfordium |
104 |
Sm |
Samarium |
62 |
Sc |
Scandium |
21 |
Sg |
Seaborgium |
106 |
Se |
Selenium |
34 |
Si |
Silicon |
14 |
Ag |
Silver |
47 |
Na |
Sodium |
11 |
Sr |
Strontium |
38 |
S |
Sulphur/Sulfur |
16 |
Ta |
Tantalum |
73 |
Tc |
Technetium |
43 |
Te |
Tellurium |
52 |
Ts |
Tennessine |
117 |
Tb |
Terbium |
65 |
Tl |
Thallium |
81 |
Th |
Thorium |
90 |
Tm |
Thulium |
69 |
Sn |
Tin |
50 |
Ti |
Titanium |
22 |
W |
Tungsten |
74 |
U |
Uranium |
92 |
V |
Vanadium |
23 |
Xe |
Xenon |
54 |
Yb |
Ytterbium |
70 |
Y |
Yttrium |
39 |
Zn |
Zinc |
30 |
Zr |
Zirconium |
40 |
|
No elements synthesised or named beyond Z = 118
TOP OF PAGE
WHAT NEXT?
For non-A level
students
KS4 Science GCSE/IGCSE
Periodic Table notes
- including simplified historical comments
INORGANIC Part 1
Historical Introduction page sub-index: 1.1 The
early classification of Antoine Lavoisier of 1789 * 1.2 The 1829 work of
Johann Döbereiner *
1.3 The work of John
Newlands 1864 * 1.4 Dmitri Mendeleev's
Periodic Table and Lothar-Meyer graphs of ~1869 * 1.5 A modern Periodic Table based on the electronic structure of
atoms * 1.6 Where did the elements come from
originally and where do we get the elements from today?
Advanced
Level Inorganic Chemistry Periodic Table Index *
Part 1
Periodic Table history
* Part 2
Electron configurations, spectroscopy,
hydrogen spectrum,
ionisation energies *
Part 3
Period 1 survey H to He *
Part 4
Period 2 survey Li to Ne * Part
5 Period 3 survey Na to Ar *
Part 6
Period 4 survey K to Kr and important trends
down a group *
Part 7
s-block Groups 1/2 Alkali Metals/Alkaline Earth Metals *
Part 8
p-block Groups 3/13 to 0/18 *
Part 9
Group 7/17 The Halogens *
Part 10
3d block elements & Transition Metal Series
*
Part 11
Group & Series data & periodicity plots * All
11 Parts have
their own sub-indexes near the top of the pages
periodic table history nuclear physics
origin of elements nuclear equations for AQA AS chemistry, periodic table
history nuclear physics origin of elements nuclear equations for Edexcel AS
chemistry, periodic table history nuclear physics origin of elements nuclear
equations for OCR AS chemistry A, periodic table history nuclear physics
origin of elements nuclear equations for OCR Salters AS chemistry B,
periodic table history nuclear physics origin of elements nuclear equations
for AQA A level chemistry, periodic table history nuclear physics origin of
elements nuclear equations for Edexcel A level chemistry, periodic table
history nuclear physics origin of elements nuclear equations for OCR A level
chemistry A, periodic table history nuclear physics origin of elements
nuclear equations for OCR Salters A level chemistry B periodic table history
nuclear physics origin of elements nuclear equations for US Honours grade 11
grade 12 periodic table history nuclear physics origin of elements nuclear
equations for pre-university chemistry courses group/series periodic table
position of element Ac Actinium 89, group/series periodic table position of
element Al Aluminium/Aluminum 13, group/series periodic table position of
element Am Americium 95, group/series periodic table position of element Sb
Antimony 51, group/series periodic table position of element Ar Argon 18,
group/series periodic table position of element As Arsenic 33, group/series
periodic table position of element At Astatine 85, Ba Barium 56,
group/series periodic table position of element Bk Berkelium 97,
group/series periodic table position of element Be Beryllium 4, group/series
periodic table position of element Bi Bismuth 83, group/series periodic
table position of element Bh Bohrium 107, group/series periodic table
position of element B Boron 5, group/series periodic table position of
element Br Bromine 35, group/series periodic table position of element Cd
Cadmium 48, group/series periodic table position of element Cs
Caesium/Cesium 55, group/series periodic table position of element Ca
Calcium 20, group/series periodic table position of element Cf Californium
98, group/series periodic table position of element C Carbon 6, group/series
periodic table position of element Ce Cerium 58, group/series periodic table
position of element Cl Chlorine 17, group/series periodic table position of
element Cr Chromium 24, group/series periodic table position of element Co
Cobalt 27, group/series periodic table position of element Cn Copernicium
112, group/series periodic table position of element Cu Copper 29,
group/series periodic table position of element, Cm Curium 96, group/series
periodic table position of element Ds Darmstadtium 110, group/series
periodic table position of element Db Dubnium 105, group/series periodic
table position of element Dy Dysprosium 66, group/series periodic table
position of element Es Einsteinium 99, group/series periodic table position
of element Er Erbium 68, group/series periodic table position of element Eu
Europium 63, group/series periodic table position of element Fm Fermium 100,
group/series periodic table position of element Fl Flerovium 114,
group/series periodic table position of element F Fluorine 9, group/series
periodic table position of element Fr Francium 87, group/series periodic
table position of element Gd Gadolinium 64, group/series periodic table
position of element Ga Gallium 31, group/series periodic table position of
element Ge Germanium 32, group/series periodic table position of element Au
Gold 79, group/series periodic table position of element Hf Hafnium 72,
group/series periodic table position of element Hs Hassium 108, group/series
periodic table position of element He Helium 2, group/series periodic table
position of element Ho Holmium 67, group/series periodic table position of
element H Hydrogen 1, group/series periodic table position of element In
Indium 49, group/series periodic table position of element I Iodine 53,
group/series periodic table position of element Ir Iridium 77, group/series
periodic table position of element Fe Iron 26, group/series periodic table
position of element Kr Krypton 36, group/series periodic table position of
element La Lanthanum 57, group/series periodic table position of element Lw
Lawrencium 103, group/series periodic table position of element Pb Lead 82,
group/series periodic table position of element Li Lithium 3, group/series
periodic table position of element Lv Livermorium 116, group/series periodic
table position of element Lu Lutetium 71, group/series periodic table
position of element Mg Magnesium 12, group/series periodic table position of
element Mn Manganese 25, group/series periodic table position of element Mt
Meitnerium 109, group/series periodic table position of element Md
Mendelevium 101, group/series periodic table position of element Hg Mercury
80, group/series periodic table position of element Mo Molybdenum 42,
group/series periodic table position of element Mc Moscovium 115,
group/series periodic table position of element Nd Neodymium 60,
group/series periodic table position of element Ne Neon 10, group/series
periodic table position of element Np Neptunium 93, group/series periodic
table position of element Ni Nickel 28, group/series periodic table position
of element Nh Nihonium 113, group/series periodic table position of element
Nb Niobium 41, group/series periodic table position of element N Nitrogen 7,
group/series periodic table position of element No Nobelium 102,
group/series periodic table position of element Og Oganesson 117,
group/series periodic table position of element Os Osmium 76, group/series
periodic table position of element O Oxygen 8, group/series periodic table
position of element Pd Palladium 46, group/series periodic table position of
element P Phosphorus 15, group/series periodic table position of element Pt
Platinum 78, group/series periodic table position of element Pu Plutonium
94, group/series periodic table position of element Po Polonium 84,
group/series periodic table position of element K Potassium 19, group/series
periodic table position of element Pr Praseodymium 59, group/series periodic
table position of element Pm Promethium 61, group/series periodic table
position of element Pa Protactinium 91, group/series periodic table position
of element Ra Radium 88, group/series periodic table position of element Rn
Radon 86, group/series periodic table position of element Re Rhenium 75,
group/series periodic table position of element Rh Rhodium 45, group/series
periodic table position of element Rg Roentgenium 111, group/series periodic
table position of element Rb Rubidium 37, group/series periodic table
position of element Ru Ruthenium 44, group/series periodic table position of
element Rf Rutherfordium 104, group/series periodic
table position of
element Sm Samarium 62, group/series periodic table position of element Sc
Scandium 21, group/series periodic table position of element Sg Seaborgium
106, group/series periodic table position of element Se Selenium 34,
group/series periodic table position of element Si Silicon 14, group/series
periodic table position of element Ag Silver 47, group/series periodic table
position of element Na Sodium 11, group/series periodic table position of
element Sr Strontium 38, group/series periodic table position of element S
Sulphur/Sulfur 16, group/series periodic table position of element Ta
Tantalum 73, group/series periodic table position of element Tc Technetium
43, group/series periodic table position of element Te Tellurium 52,
group/series periodic table position of element Ts Tennessine 117,
group/series periodic table position of element Tb Terbium 65, group/series
periodic table position of element Tl Thallium 81, group/series periodic
table position of element Th Thorium 90, group/series periodic table
position of element Tm Thulium 69, group/series periodic table position of
element Sn Tin 50, group/series periodic table position of element Ti
Titanium 22, group/series periodic table position of element W Tungsten 74,
group/series periodic table position of element U Uranium 92, group/series
periodic table position of element V Vanadium 23, group/series periodic
table position of element Xe Xenon 54, group/series periodic table position
of element Yb Ytterbium 70, group/series periodic table position of element
Y Yttrium 39, group/series periodic table position of element Zn Zinc 30,
group/series periodic table position of element Zr Zirconium 40 studying
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For non-A level
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KS4 Science GCSE/IGCSE
Periodic Table notes
- including simplified historical comments
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