04/01/12EdExcel Additional Science   Chemical Structures      W Richards    The Weald School
Compounds                                               04/01/12Compounds are formedwhen two or moreelements arechemically...
Some simple compounds…                                        04/01/12                                CarbonMethane, CH4  ...
Bonding Revision                                                04/01/12Cl        Hi. My name’s Johnny Chlorine.          ...
Ionic Bonding Revision                                                              04/01/12Cl                 Here comes ...
Covalent Bonding                                                             04/01/12Cl                            Here co...
Covalent bonding                                                                      04/01/12Consider an atom of hydrogen...
Dot and Cross Diagrams                         04/01/12 Water, H2O:                     HH              O
Dot and Cross Diagrams                         04/01/12Oxygen, O2:    O         O
Dot and cross diagrams                                                                 04/01/12                           ...
Dot and cross diagrams                                               04/01/12Nitrogen, N2:                Methane CH4:    ...
04/01/12 Other ways of drawing covalent bondsConsider ammonia (NH3):  H     N     H        H                          H   ...
Group 7 – The halogens                         04/01/12                         F                         Cl              ...
The Halogens - Chlorine                                   04/01/12         Each molecule has a strong force         holdin...
The Halogens - Bromine                                   04/01/12         The forces between molecules are         slightl...
The Halogens - Iodine                                                   04/01/12Iodine is a solid at room temperature but ...
Forms of Carbon                                                       04/01/12                 1) Diamond – very hard, doe...
Metals                                                                           04/01/12                                 ...
Nanoscience                                                      04/01/12 Nanoscience is a new branch of science that refe...
04/01/12Different ways of modelling atoms   H   N    H        H   N   H       H                 H
Chemical-based Therapy                                                          04/01/12Chemical-based therapy is the use ...
Homeopathy                                                        04/01/12Homeopathic medicines are drugs that contain com...
Homeopathy                              04/01/12For                 Against       Homeopathy
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Ed chemical structures

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Ed chemical structures

  1. 1. 04/01/12EdExcel Additional Science Chemical Structures W Richards The Weald School
  2. 2. Compounds 04/01/12Compounds are formedwhen two or moreelements arechemically combined.Some examples: Methane Sodium chloride (salt) Glucose
  3. 3. Some simple compounds… 04/01/12 CarbonMethane, CH4 Water, H2O dioxide, CO2 Key Hydrogen OxygenEthyne, C2H2 Sulphuric Carbon acid, H2SO4 Sulphur
  4. 4. Bonding Revision 04/01/12Cl Hi. My name’s Johnny Chlorine. I’m in Group 7, so I have 7 electrons in my outer shell Cl I’d quite like to have a full outer shell. To do this I need to GAIN an electron. Who can help me?
  5. 5. Ionic Bonding Revision 04/01/12Cl Here comes my friend again, Sophie Sodium Na Hey Johnny. I’m in Group 1 so I have one electron in my outer shell. Unlike Harry, this electron is far away from the nucleus so I’m quite happy to get Okay rid of it. Do you want it? - + Cl Na Now we’ve both got full outer shells and we’ve both gained a charge. We’ve formed an IONIC bond.
  6. 6. Covalent Bonding 04/01/12Cl Here comes another one of my friends, Harry Hydrogen Hey Johnny. I’ve only got one electron but it’s really close to H my nucleus so I don’t want to lose it. Fancy sharing? Cl H Now we’re both really stable. We’ve formed a covalent bond.
  7. 7. Covalent bonding 04/01/12Consider an atom of hydrogen: Notice that hydrogen has just __ electron in its outer shell. A full (inner) shell would have __ electrons, so two hydrogen atoms get together and “_____” their electrons: Now they both have a ____ outer shell and are more _____. The formula for this molecule is H2.When two or more atoms bond by sharing electrons wecall it ____________ BONDING. This type of bondingnormally occurs between _______ atoms. It causes theatoms in a molecule to be held together very stronglybut there are ____ forces between individual molecules.This is why covalently-bonded molecules have low meltingand boiling points (i.e. they are usually ____ or ______). Words – gas, covalent, non-metal, 1, 2, liquid, share, full, weak, stable
  8. 8. Dot and Cross Diagrams 04/01/12 Water, H2O: HH O
  9. 9. Dot and Cross Diagrams 04/01/12Oxygen, O2: O O
  10. 10. Dot and cross diagrams 04/01/12 Water, H2O:Step 1: Draw the atoms with Step 2: Put the atoms together andtheir outer shell: check they all have a full outer shell: H O H O H H Oxygen, O2: O O O O
  11. 11. Dot and cross diagrams 04/01/12Nitrogen, N2: Methane CH4: H N N H C H HAmmonia NH3: Carbon dioxide, CO2: H N H O C O H
  12. 12. 04/01/12 Other ways of drawing covalent bondsConsider ammonia (NH3): H N H H H N H H H N H H
  13. 13. Group 7 – The halogens 04/01/12 F Cl Br I At
  14. 14. The Halogens - Chlorine 04/01/12 Each molecule has a strong force holding the atoms together, but the forces between molecules are very weak so chlorine is a gas at room temperature
  15. 15. The Halogens - Bromine 04/01/12 The forces between molecules are slightly stronger so bromine is a liquid at room temperature.
  16. 16. The Halogens - Iodine 04/01/12Iodine is a solid at room temperature but with gentleheating it will melt. The atoms will remain in pairs.
  17. 17. Forms of Carbon 04/01/12 1) Diamond – very hard, doesn’t conduct electricity, very high melting point2) Graphite – soft, does conductelectricity, very high melting point 3) Buckminsterfullerene – 60 carbon atoms arranged in a sphere
  18. 18. Metals 04/01/12 + + +Metals are defined as elements that readilylose electrons to form positive ions. There + + +are a number of ways of drawing them: + + + - - + + + + + + - - + + + + - - + + + - + + + - Delocalised electrons
  19. 19. Nanoscience 04/01/12 Nanoscience is a new branch of science that refers to structures built from a few hundred atoms and are 1-100nm big. They show different properties to the same materials in bulk. They also have a large surface area to volume ratio and their properties could lead to new developments in computers, building materials etc.Task: research nanoscienceand find two current and/orfuture applications of thisscience.
  20. 20. 04/01/12Different ways of modelling atoms H N H H N H H H
  21. 21. Chemical-based Therapy 04/01/12Chemical-based therapy is the use of chemicals to alleviate anillness. Here are two examples:Chemotherapy – drugs that are used to kill cancer cellsAntibiotics – drugs that are used to kill bacteria that causeillnesses such as tuberculosis and cholera
  22. 22. Homeopathy 04/01/12Homeopathic medicines are drugs that contain compoundsthat, if strong enough, would cause an illness. These drugsinduce symptoms so that the body is “kick-started” intostarting the natural healing process.
  23. 23. Homeopathy 04/01/12For Against Homeopathy

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