Bonding & Properties

Question 1

what is ionic bonding

Answer 1

the strong electrostatic forces of attraction between oppositely charged ions held in a lattice

Question 2

why do ionic substances have high mp and bp

Answer 2

b/c it takes a lot of energy to break the strong electrostatic attraction between the ions

Question 3

why do ionic compounds conduct electricity

Answer 3

when molten/dissolved ions are free to move and carry charge

Question 4

what is covalent bonding

Answer 4

occurs between 2 non metals
sharing of electrons
The positive nucleus of each atom has an attraction for the bonding electrons shared in the covalent bond

strong covalent bonds between atoms, weak van der Waals forces of attraction between molecules

Question 5

are there any lone pairs of electrons in simple covalent bonding

Answer 5

no

Question 6

why cant simple molecular covalent molecules conduct electricity

Answer 6

no free electrons to carry charge

Question 7

why do simple molecular substances have LOW mp and bp

Answer 7

weak van der Waals forces of attraction are easy to overcome

Question 8

what is macromolecular covalent bonding

Answer 8

lattice of many atoms held together by strong covalent bonds

Question 9

why do substances w macromolecular covalent bonds have HIGH mp and bp

Answer 9

it takes a lot of energy to overcome many strong covalent bonds

Question 10

describe the structure of graphite

Answer 10

• macromolecular covalent
• each C atom bonded to 3 others
• in layers
• weak van der Waals forces between layers so layers can slide over eachother = soft + slippery
• one e- from each C is delocalised and can carry charge = can conduct electricity

Question 11

describe metallic bonding

Answer 11

lattice of positive metal ions strongly attracted to a sea of delocalised e-
malleable - layers can slide over eachother

Question 12

do metallic compounds have high or low mp and bp and why?

Answer 12

high
strong forces of attraction between +tive metal ions and -tive delocalised e-

Question 13

why can metallic compounds conduct electricity

Answer 13

delocalised e- can move throughout the metal to carry charge

Question 14

how does the strength of metallic bonds change across the periodic table? Why?

Answer 14

Increases across table
b/c higher charge on metal ions
more delocalised e- per ion
stronger force of attraction between them

Question 15

what is a dative covalent bond?

Answer 15

is a covalent bond in which both electrons come from the same atom

Question 16

how is a dative covalent bond drawn?

Answer 16

A dative covalent bond is drawn using an arrow from the donated pair of electrons to the electron-deficient atom.