Chemistry C4
- Created by: Avani.Shanbhag27
- Created on: 25-01-16 17:27
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- C4 - Chemical Patterns
- Creation- Periodic Table
- Mendeleev
- Organised atoms in order of protons, neutrons and electrons
- He was the only scientist who left gaps for new atoms that would be discovered in the future
- Flame test colours were unique for each atom and could be spotted on a line spectrum
- Electrons have a negative charge of -1
- Neutrons have a charge of 0. This means that the nucleus has an overall positive charge.
- This means that the nucleus has an overall positive charge.
- Electron configuration is 2.8.8.8.....
- A complete first shell has 2 electrons. The rest of the shells need 8 to be complete.
- Mendeleev
- Group 1 (Alkali Earth Metals)
- Reactivity increases as metals go down.
- More electrons = higher reactivity
- Least reactive is Lithium, which only has 3 electrons in its outer shell - stronger forces between nucleus and electrons so it cannot lose elctrons easily
- Most reactive is Francium, which has 87 electrons in its outer shell - weaker forces between nucleus and electrons so it is easier for it to lose electrons during a reaction, it is therefore very reactive
- Has one extra electron on its outer shell, wants to lose it during a reaction.
- React violently with water. Hydrogen and a metal hydroxide (alkali) is formed.
- The metals are highly flammable and the hydroxides produced are corrosive and harmful.
- Reactivity increases as metals go down.
- Group 7 (Halogens)
- Reactivity increases as gases go up
- Less electrons = higher reactivity
- Most reactive is Fluorine, which has 9 electrons in its outer shell - there are stronger forces between the nucleus and electrons so electrons that are given out during the reaction are very easily attracted to the shell.
- Least reactive is Astatine, which has 85 electrons in its outer shell - there are weaker forces between the nucleus and electrons so it is a lot harder for it to attract more electrons.
- Have one less electron on their outer shell, these want to gain one electron to be left with a full shell after the reaction.
- All are diatomic molecules. There is 2 atoms joined together. There are covalent bonds between them which allow to share the electrons and have temporary full outer shells.
- Reactivity increases as gases go up
- Ionic Compounds
- Crystal lattice - all ions (charged particles) are arranged in a compact regular pattern.
- Ionic compounds are soluble in water and they conduct electricity when melted. When it is melted, the ions are free to move to the electrodes.
- In a reaction between Sodium Chloride and Fluorine, the Fluorine would DISPLACE the chlorine because it is more reactive. This is called a displacement reaction - where the more reactive atom of the group will replace the other when it is part of a compound.
- Creation- Periodic Table
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