Bonding

Question 1

Define ionic bonding

Answer 1

Electrostatic force of attraction between oppositely charged ions

Question 2

Give three molecules that are an example of iconic bonding

Answer 2

MgO
NaCl
KI

Question 3

Define covalent bonding

Answer 3

A shared pair of electrons between two non-metals

Question 4

Give three molecules that are an example of covalent bonding

Answer 4

CH3
H2O
CO2

Question 5

Define dative covalent bonding

Answer 5

The shared pair of electrons in the covalent bond coming from only one of the bonding atoms

Question 6

Give two molecules that are an example of dative covalent bonding

Answer 6

NH4+
H3O+
NH3BF3

Question 7

Define metallic bonding

Answer 7

The electrostatic force of attraction between the positive metal ions and the sea of delocalised electrons

Question 8

What are the four crystal structures?

Answer 8

Giant Ionic lattice
Simple molecular
Macromolecular
Metallic

Question 9

Name the macromolecular crystals and define macromolecular

Answer 9

Giant molecular structures joined by covalent bonds

Diamond
Graphite
Silicon dioxide
Silicon

Question 10

Explain the trend in boiling points for ionic, covalent and metallically bonded molecules

Answer 10

Ionic- high because if the giant ionic lattice of ions with strong electrostatic forces between oppositely charged ions.

Molecular- low because of weak intermolecular forces between molecules (vdw’s)

Macromolecular- high because of many strong covalent bonds and require high amounts of energy to overcome.

Metallic- high because of strong electrostatic forces between positive ions and sea of delocalised electrons.

Question 11

Name all the shapes of the molecules with their correlating bond angle

Answer 11

Linear- 180
Trigonal planar- 120
Tetrahedral- 109.5
Bent- 104.5
Trigonal Bipyramidal- 120 and 90
Octahedral- 90

Question 12

Explain what the ‘VERT’ theory is

Answer 12

Pairs of electrons in the outer shell of atoms arrange themselves as far as possible to minimise repulsion.

Question 13

What does a lone pair affect when drawing molecules?

Answer 13

The bond angle by 2.5

Question 14

Define electronegativity

Answer 14

The relative tendency of an atom in a covalent bond in a molecule to attract molecules to itself

Question 15

What makes a molecule polar?

Answer 15

Difference in electro negativity

Question 16

Why do some polar bonds not form dipoles?

Answer 16

The electro negativity difference is too little
The bonds are symmetrical and cancel out

Question 17

What are the three IMF’s in order of strength

(Weakest to strongest)

Answer 17

Van Der Waals
Permanent dipole dipole
Hydrogen bonding

Question 18

Explain how IMF’s affect melting and boiling points

Answer 18

VDW’s- as the molecule gets bigger the number of van der waals between the molecules increases

Permanent dipole dipole- stronger than vdw’s so they have higher melting and boiling points

Hydrogen bonding- high points are caused by increasing vdw’s

Question 19

What causes ice to be less dense than water?

Answer 19

Solids are denser than the liquid as the particles in a solid are more closely packed together than in liquid state.
The water molecules affect into an open lattice and have a relatively long bond length of hydrogen bonds so the water molecules are slightly further part in the liquid.

Question 20

Give examples of giant ionic lattices

Answer 20

Sodium chloride
Magnesium chloride

Question 21

Define simple molecular and give examples

Answer 21

Molecules that have been covalently bonded, with intermolecular forces between them.

Iodine
Ice
Carbon dioxide
Water
Methane

Question 22

Give examples of giant metallic lattices

Answer 22

Mg
Na