3.1.3 Bonding Flashcards
What do physical/chemical properties of compounds depend on
Depend on the way compounds are held together by chemical bonds and intermolecular forces
Define ionic bonding
The electrostatic attraction between oppositely charged ions in a giant ionic lattice
Describe ionic lattices
Giant, regular repeating arrangement of ions
Crystal structures
Properties of ionic compounds
Strong electrostatic forces require lots of energy to overcome, so they have high melting/boiling points
Once molten, ions are free to move and can conduct an electric current
Often ionic compounds are soluble in water
Define a covalent bond
Electrostatic attraction between the nuclei and the shared pair of electrons
Non metals bonded together
Electron pair(s) shared
Describe singular molecular structures
Although covalent bonds are strong, molecules are not strongly attracted to eachother
Covalently bonded compounds have a small difference in electronegativity
Co-ordinate bonding:
A covalent bond where one of the atoms provides both of the electrons which form the bond
What is coordinate bonding also known as
Dative bonding
Where do arrows point towards in a dative bond
Towards the recipient ion
Describe metallic bonding
Involves the attraction between a ‘sea of delocalised electrons’ and positive ions arranged in a lattice
Properties of metals
Good conductors - delocalised electrons
High melting points - giant structures, electrostatic attraction between positive metal cations and delocalised electrons
Malleable/ductile - ions can slide over each other
What does the strength of a metal depend on
-size of the charge on the ion
-size of the ion
What are crystals
Solids in which the particles have a regular arrangement and are held together by forces of attraction
Four basic crystal types
Ionic
Metallic
Molecular
Macromolecular (giant covalent)
How much stronger are covalent bonds than hydrogen bonds
10 times