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KS3 Science Quizzes

GCSE KS4 Science-Chemistry

Advanced Level Chemistry

docb4_72bond5 updated April 6th 2008

KS4 SCIENCE - Additional & Applied Chemistry help AQA GCSE Science - Chemistry CCEA GCSE Science - Chemistry Edexcel GCSE 360Science - Chemistry OCR GCSE 21st Century Science Suite - Chemistry  OCR GCSE Gateway Science Suite - Chemistry OCR GCSE Applied Science - Chemistry (double award) WJEC GCSE Science - Chemistry

useful alphabetical site indexdoc b's HOMEPAGE Site-Map for KS3 Science-GCSE-GCE-AS-A2-IB Chemistry Doc Brown's Chemistry Clinic

GCSE-IGCSE KS4 Science-CHEMISTRY and AS (basic) Chemistry Revision-Information Notes on

 The Structure and properties of substances - Ionic, Covalent & Metallic Bonding 

Part 1 Introduction - why do atoms bond together? & sub-index for Parts 2-5 (read 1st)

Part 2 Ionic Bonding - compounds and properties

Part 3 Covalent Bonding -small simple molecules and properties

Part 4 Covalent Bonding - macromolecules and giant covalent structures

Part 5 Metallic Bonding - structure and properties of metals (this page)

Part 6 More advanced concepts for advanced level chemistry (in preparation)



Part 5.  METALLIC BONDING - structure and properties of metals

metal bonding model element/alloys * physical properties of metals


(c) doc b BONDING IN METALS

  • (c) doc bThe crystal lattice of metals consists of ions NOT atoms surrounded by a 'sea of electrons' forming another type of giant lattice.
  • The outer electrons (-) from the original metal atoms are free to move around between the positive metal ions formed (+).
  • These free or 'delocalised' electrons are the 'electronic glue' holding the particles together.
  • There is a strong electrical force of attraction between these mobile electrons (-) and the 'immobile' positive metal ions (+) and this is the metallic bond.

 Explaining the physical properties of metals

  • This strong bonding generally results in dense, strong materials with high melting and boiling points.

    • Usually a relatively large amount of energy is needed to melt or boil metals. Energy changes for the physical changes of state of melting and boiling for a range of differently bonded substances are compared in a section of the Energetics Notes.

  • Metals are good conductors of electricity because these 'free' electrons carry the charge of an electric current when a potential difference (voltage!) is applied across a piece of metal.

  • Metals are also good conductors of heat. This is also due to the free moving electrons. Non-metallic solids conduct heat energy by hotter more strongly vibrating atoms, knocking against cooler less strongly vibrating atoms to pass the particle kinetic energy on. In metals, as well as this effect, the 'hot' high kinetic energy electrons move around freely to transfer the particle kinetic energy more efficiently to 'cooler' atoms.

  • Typical metals also have a silvery surface but remember this may be easily tarnished by corrosive oxidation in air and water.

  • Unlike ionic solids, metals are very malleable, they can be readily bent, pressed or hammered into shape. The layers of atoms can slide over each other without fracturing the structure (see below). The reason for this is the mobility of the electrons. When planes of metal atoms are 'bent' or slide the electrons can run in between the atoms and maintain a strong bonding situation. This can't happen in ionic solids.

  • For more on the properties and uses of metals see Transition Metals and Extra Industrial Chemistry pages and the note and diagram below.

 Note on Alloy Structure

(c) doc b

  1. Shows the regular arrangement of the atoms in a metal crystal and the white spaces show where the free electrons are (yellow circles actually positive metal ions).
  2. Shows what happens when the metal is stressed by a strong force. The layers of atoms can slide over each other and the bonding is maintained as the mobile electrons keep in contact with atoms, so the metal remains intact BUT a different shape.
  3. Shows an alloy mixture. It is NOT a compound but a physical mixing of a metal plus at least one other material (shown by red circle, it can be another metal e.g. Ni, a non-metal e.g. C or a compound of carbon or manganese, and it can be bigger or smaller than iron atoms). Many alloys are produced to give a stronger metal. The presence of the other atoms (smaller or bigger) disrupts the symmetry of the layers and reduces the 'slip ability' of one layer next to another. The result is a stronger harder less malleable metal.
  4. The main point about using alloys is that you can make up, and try out, all sorts of different compositions until you find the one that best suits the required purpose.

ks4 national curriculum science examinations e-gcse-igcse chemistry revision *  ks4 national curriculum science examinations-gcse-igcse chemistry revision *  ks4 national curriculum  science examinations-gcse-igcse chemistry revision *  ks4 science examinations-gcse-igcse chemistry revision *  ks4 science examinations-gcse-igcse chemistry revision *  ks4 science examinations-gcse-igcse chemistry revision * SITE PURPOSE EDUCATION - online learning or 'self-private-tuition' using revision notes, quizzes, practice tests involving GCSE Science CHEMISTRY in the areas of REVISING only the CHEMISTRY-Earth Science-Radioactivity at Doc Brown's Chemistry Clinic via HOMEPAGE in secondary school/schools, 6th form college/colleges, academy/academies or home self-study. Hopefully it will encourage interest and understanding of Chemistry, Earth Science and Radioactivity in any country of the world, though the site is written entirely in English. The website is designed to help and unofficially support students/teachers revise-learn/teach the chemistry for modular or co-ordinated examination science courses from UK QCA based AQA, OCR (Oxford and Cambridge) Twenty First (21st) Century and Gateway Science, Edexcel 360Science , Nuffield, Salters, Cambridge International (CIE), London International, WJEC, CCEA exams etc. Also, national award assessments-examinations for GCSE-IGCSE-KS4-O level-BTEC-NVQ applied, additional and chemistry national curriculum science courses. The notes should also provide some background theory for a coursework assignment or project. BUT please note that my on-line revision notes and quizzes are no substitute for good classroom teaching-lecturing and thorough studying of your own notes and textbooks, practicing past papers and a copy of the syllabus which are readily downloaded from the examination board sites, but I hope here and there they will lend a tutoring hand on some topic, unit, module etc. For final revision you have to be intellectually honest about what you don't know or follow, YOU have to take the stuff to pieces, analyse what you do/do not understand and reconstruct it so it all makes sense in the end. There is no other way, there are no magic secrets on how to revise and learn, its mainly down to hard work and just good old fashioned study and employing teach-yourself strategies without the need for extra tutors and tutoring lessons. I also think there is too much hit and miss revision using past papers (which I do NOT supply) and not enough systematic revision. I also hope it will help teachers in planning lessons and developing schemes of work for science-chemistry. There are no lesson plans on the site but there are plenty of quizzes to incorporate into classroom activities whether photocopied or on electronic whiteboard projector for use as self-tuition-assessment purposes and a variety of teaching and learning styles and the images may be used in Microsoft Word documents and powerpoint projections. The site seems to be used by a large number of home study tutors, particularly the revision notes. An individual tutor may print out the notes for science-chemistry learning teaching-tuition purposes and for background material for assignments and projects. I have no interest or time in producing WORD.doc or xxxx.pdf files of the notes at the moment. Neither have I time to write up many practical laboratory experiments ('lab'-'labs') at the moment, but the notes contain lots of background information of chemical reactions in terms of observations-balanced equations-reactants-products-theory etc. I also find it difficult to recommend specific exam websites or syllabus textbooks, it depends exactly on what you need, what you have time for, and there are so many of them to choose from and I do not supply past examination papers for classes. The sites resources include revision notes, quizzes and worksheets which provide support for home study or tuition for homework and coursework help e.g. science investigations for any of the key stage courses indicated, but I do not supply lesson plans. *  ks4 science examinations e-gcse-igcse chemistry revision *  ks4 science examinations-gcse-igcse chemistry revision *  ks4 science examinations-gcse-igcse chemistry revision *  ks4 science examinations-gcse-igcse chemistry revision *  ks4 science examinations-gcse-igcse chemistry revision *  ks4 science examinations-gcse-igcse chemistry revision * Dr W P Brown Feb 15th 2008

useful alphabetical site indexdoc b's HOMEPAGE Site-Map for KS3 Science-GCSE-GCE-AS-A2-IB Chemistry

Online free help resources for Key Stage 4 AQA, Edexcel, OCR, CIE GCSE IGCSE BTEC Science, GCE, AS, A2 Advanced subsidiary Chemistry A levels, IB Diploma and US K12 (K-12 grades) courses and examinations and revising for the various syllabuses and specifications. Exploring the site for lessons, plans, ideas for projects and coursework, professional development. Through hard work the site has been built up over the course of many years with no need of special pc software except FrontPage and Hot Potatoes (uvic) for quizzes and worksheets. It is used in the classroom, home learning-tutoring-schooling and guidance, private tuition, school retakes revision. Whether you are a teacher/tutor teaching, a student studying, using the pages as self-study guides for your science-chemistry studies etc. etc. I hope the site supports your endeavour. 15-12-07 © Dr W P Brown

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KS3 Science Quizzes

GCSE KS4 Science-Chemistry

Advanced Level Chemistry

docb4_72bond5 updated April 6th 2008

KS4 SCIENCE - Additional & Applied Chemistry help AQA GCSE Science - Chemistry CCEA GCSE Science - Chemistry Edexcel GCSE 360Science - Chemistry OCR GCSE 21st Century Science Suite - Chemistry  OCR GCSE Gateway Science Suite - Chemistry OCR GCSE Applied Science - Chemistry (double award) WJEC GCSE Science - Chemistry

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