How do you calculate relative atomic mass for isotopes?
Times the mass and percentage of isotopes together add the resultsand divide by 100.
What is a positive ion called?
Cation
What is a negative ion called?
Anion
What is an ionic bond?
A strong electrostatic attraction between oppositely charged ions.
Describe the structure of ionic compounds:
Giant lattice of ionic compounds as a regular arrangement of alternating positive and negative ions.
What type of elements do ionic bonds occur between?
Metallic and non metallic
2 properties of ionic compounds:
- High melting and boiling points
- Good electrical conductivity when aqueous or molten - poor when solid. (so charges/ions can flow freely)
What is a covalent bond?
A covalent bond is formed when a pair of electrons is shared between two atoms leading to noble gas electroninc configurations
2 properties of covalent bonded compounds:
- Low melting and boilings points - weak intermolecular forces
- Poor electrical conductivity
2 giant covalent structures?
- Diamond - cutting tools
- Graphite - lubricant and electrode
What is the structure of silicon (IV) oxide? SiO2
Each oxygen atom forms covalent bonds with 2 silicon atoms and each silicon atom in turn forms covalent bonds with 4 oxygen atoms. Tetrahedron
What is metallic bonding?
The bonding from electrostatic attraction between the positive ions in a giant metallic lattice and a ‘sea’ of delocalised electrons
2 Physical Properties of metallic bonded substances:
- Good electrical conductivity
- Malleability and ductility
