Chemsheets AS June-2015

IONIC e.g. NaCl

SIMPLE MOLECULAR e.g. CH 4

SIMPLE MOLECULAR e.g. I 2

II II II II II II I I II I I II I I I I SOLID I 2 LIQUID I 2 GAS I 2

PROPERTYEXPLANATION Melting & boiling points LOW Weak forces between molecules Electrical conductivity DOES NOT CONDUCT No mobile charged particles StrengthBRITTLE Weak forces between molecules Solubility in water SLIGHTLY SOLUBLE

SIMPLE MOLECULAR e.g. ice

PROPERTYEXPLANATION Melting & boiling points LOW Weak forces between molecules Electrical conductivity DOES NOT CONDUCT No mobile charged particles Density of ice v water ICE IS LESS DENSE THAN WATER In ice molecules are arranged in lattice due to H-bonds; as a liquid molecules are closer as not in lattice

GIANT COVALENT e.g. SiO 2

GIANT COVALENT e.g. diamond Great rotatable structures (but they are NOT molecules!!)

GIANT COVALENT e.g. diamond

PROPERTYEXPLANATION Melting & boiling points VERY HIGH Need to break all strong covalent bonds Electrical conductivity DOES NOT CONDUCT No mobile charged particles StrengthSTRONG Rigid arrangement of atoms held by covalent bonds Solubility in water INSOLUBLE

GIANT COVALENT e.g. graphite Great rotatable structures (but they are NOT molecules!!)

GIANT COVALENT e.g. graphite

PROPERTYEXPLANATION Melting & boiling points VERY HIGH Need to break all strong covalent bonds Electrical conductivity CONDUCTS Some electrons free to move between layers StrengthBRITTLE Weak forces between layers so layers can slide Solubility in water INSOLUBLE

C Graphene GIANT COVALENT e.g. graphene

METALLIC e.g. Mg

PROPERTYEXPLANATION Melting & boiling points HIGH Strong attraction between +ve ions and delocalised e-’s Electrical conductivity CONDUCTS Outer shell electrons free to move StrengthSTRONG Layers can slide while maintaining metallic bonding Solubility in water INSOLUBLE

Rank these metals in order of melting points: Sodium Potassium Magnesium

e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- Sodium (Na) 2+ e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- Potassium (K) Magnesium (Mg)

e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- Sodium (Na) Mpt 98ºC 2+ e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- Potassium (K) Mpt 64ºC Magnesium (Mg) Mpt 650ºC

e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- Sodium (Na) Mpt 98ºC Con e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- e- Potassium (K) Mpt 64ºC Con Magnesium (Mg) Mpt 650ºC Con Con = Electrical conductivity (measured as  -1 m -1 )