- Created by: abbiedye
- Created on: 24-07-18 19:34
How are ions formed?
- Ions are charged particles (Cl- or Mg2+)
- Ions are formed when atoms gain or lose electrons
- They do this to get a full outer shell - outer shells are very stable
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What elements form what ions?
- Group 1 and 2 elements lose electrons to form positive ions
- Group 6 and 7 elements gain electrons to form negative ions
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Which groups are most likely to form ions?
- Groups 1+2 and 6+7
- Group 1 and 2 elements are metals and lose electrons - positive ions (cations)
- Group 6 and 7 elements are non-metals and gain electrons - negative ions (anions)
- Group 1 elements = 1+ ions
- Group 2 elements = 2+ ions
- Group 6 elements = 2- ions
- Group 7 elements = 1- ions
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What is ionic bonding?
- Ionic bonding = transfer of electrons
- Metals and non-metals can react together
- When this happens, the metal atoms lose electrons to form positively charged ions
- The non-metal atoms gain these electrons to form negatively charger ions
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What are some examples for ionic compounds?
- Sodium Chloride (NaCl)
- Magnesium Chloride (MgCl2)
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What are ionic compounds?
- In ionic compounds, the ions are arranged in a pattern. This is called a giant ionic lattice
- There are strong electrostatic forces of attraction between oppositely charged ions
- They have similar properties
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What is covalent bonding?
- When non-metal atoms bond together, they share pairs of electrons to make covalent bonds
- Atoms only share electrons in their outer shells
- Atoms get one extra shared electron for every single covalent bond that they form
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What are simple molecular structures?
- Simple molecular substances are made up of molecules that contain a few atoms joined together by covalent bonds
- Substances containing covalent bonds usually have simple molecular structures
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What are giant covalent structures?
- In giant covalent structures, all the atoms are bonded to each other by strong covalent bonds
- They have very high melting and boiling points. This is because lots of energy is needed to break the covalent bonds
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What are the properties of simple molecular substa
- Very strong covalent bonds
- A weak attraction between molecules
- Low melting and boiling points
- Don't conduct electricity (no free electrons)
- Most substances are gases or liquids at room temperature
- As molecules get bigger, the strength of intermolecular forces increase
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What are polymers?
- In a polymer, lots of small units are joined together to form a long molecule
- All the atoms in a polymer are joined by strong covalent bonds
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What are the structures of carbon?
- Diamond - each carbon atom forms 4 bonds and takes a lot of energy to break
- Graphite - layers of carbon atoms, each atom forms three bonds in layers
- Graphene - a sheet of carbon atoms, hexagons, and the bonds make it strong and light
- Fullerenes - molecules of carbon - closed tubes or hollow balls
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What are the different allotropes of carbon?
- Diamond - very hard, high melting point, doesn't conduct electricity - no free electrons
- Graphite - sheets of hexagons, no bonds between the layers - soft, high melting point - delocalised electron = conduct
- Graphene - one layer of graphite, light, delocalised electron - conducts
- Fullerenes - closed tubes - hollow balls, hexagons, pentagons or heptagons, huge surface area
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What is metallic bonding?
- Metallic bonding involves delocalised electrons
- Metals are giant structures of atoms. They contain lots of metal atoms bonded together
- The electrons in the outer shell of the metal atoms are free to move around
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What are alloys
- Pure metals are too soft and are therefore mixed with other metals to make them harder (alloys)
- Most metals are alloys as they are combined with two or more other metals to make them stronger
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What are the states of matter?
- Solids = strong forces, held together in fixed positions, in patterns
- Liquids = weak forces, free to move, don't keep a fixed shape
- Gases = very weak forces, free to move, no fixed shape or volume
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What are the different changes of state?
- Solid -> Liquid = melting
- Liquid -> Gas = boiling
- Gas -> Liquid = condensing
- Liquid -> Solid = freezing
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