m2 - bonding

Question 1

dative covalent bond

Answer 1

covalent bond in which a shared pair of electrons are donated from one of the atoms only

Question 2

ionic bonding def

Answer 2

(strong) electrostatic attraction between positive and negative ions

Question 3

covalent bonding

Answer 3

strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms

Question 4

elements that can expand their octet

Answer 4

sulfur, phosphorus, silicon, and chlorine

Question 5

dative covalent bonded atoms will have

Answer 5

a charge

Question 6

properties of ionic compounds

Answer 6

millions of ions combine to form a giant ionic lattice. each ion is surrounded by ions of the opposite charge
(imagine NaCl diagram), each Na+ ion is surrounded by 6 Cl- ions and vice versa

HIGH MP/BP - strong ionic bonds require lots energy to break MgO higher than NaCl because 2+ 2- charge greater than 1+ 1- charge, so greater electrostatic attraction between ions

ELECTRICAL CONDUCTIVITY - not in solid as ions can’t move to carry charge - yes in molten as ions are free to move and can conduct an electrical current

SOLUBILITY - many dissolve in polar solvents like water. the solvent breaks down the giant lattice by attracting many individual ions and surrounding them to have a stabilising effect

Question 7

properties of covalent compounds

Answer 7

SIMPLE MOLECULAR:
MP/BP - low as a relatively small amount of energy is required to overcome the weak IMFs
ELECTRICAL CONDUCTIVITY - non conductors as there are no charged particles that are free to move
SOLUBILITY - generally soluble in non-polar solvents as they can form london forces with the solvent that are of similar magnitude to the forces between solvent molecules

GIANT COVALENT: (insoluble, bonds are very strong, can’t be broken down by solvent)
DIAMOND: C bonded to 4 other C in a tetrahedral arrangement.
MP/BP very high as to melt diamond, strong covalent bonds must be broken, requires a large amount of energy
ELECTRICAL CONDUCTIVITY - no, no free charged particles / e- can move

GRAPHITE: C bonded to 3 other C. 4th e- on each C is between the layers of hexagonal rings
MP/BP - high as covalent bonds need to be broken which requires a large amount of energy
ELECTRICAL CONDUCTIVITY - yes, each C atom provides an e- to a sea of electrons that can move parallel to the layers

GRAPHENE: 2D layer of carbon atoms which comprises hexagonal rings bonded together.
MP/BP - high
ELECTRICAL CONDUCTIVITY - yes, each C has one spare e-

Question 8

properties of metallic compounds

Answer 8

good conductors - delocalised e- can move and carry charge
malleable - uniform layers of positive ions can slide over each other
high mp/bp - electrostatic forces of attraction between cations and de e- very strong, take lots of energy to overcome

Question 9

metallic bonding def

Answer 9

strong electrostatic attraction between cations and delocalised electrons