Bonding and Structure (ionic bonding, covalent bonding and shapes of molecules)

Question 1

What is ionic bonding?

Answer 1

the electrostatic attraction between positive and negative ions

Question 2

What is a compound ion?

Answer 2

An ion which is made of multiple atoms

Question 3

What structure do ionic compounds have?

Answer 3

A lattice structure

Question 4

What is a giant ionic lattice structure?

Answer 4

A structure made of repeating units of identical structure

Question 5

State the three properties of ionic compounds?

Answer 5

1. They dissolve in water
2. They conduct electricity
3. They have high melting and boiling points

Question 6

Why do ionic compounds have high melting and boiling points?

Answer 6

As a lot of energy is required to break the strong electrostatic force of attraction between the oppositely charged ions

Question 7

Why do ionic compounds dissolve in water?

Answer 7

• water is a polar solvent
• polar water molecules break down the lattice and surround each ion to form a solution

Question 8

When can ionic compounds conduct electricity?

Answer 8

• When melted or dissolved in water (liquid or aqueous)

Question 9

Why can’t ionic compounds conduct electricity in the solid state?

Answer 9

As the ions are in fixed positions in the giant ionic lattice

Question 10

Why can ionic compounds conduct electricity in the liquid/aqueous state?

Answer 10

As the ionic lattice is broken down when melted or dissolved in water, so the ions are free to move and carry a charge

Question 11

What does the principle of electroneutrality state?

Answer 11

that the overall charge of a compound ion must be 0

Question 12

What is a covalent bond?

Answer 12

A shared pair of electrons

Question 13

Are covalent or ionic bonds stronger?

Answer 13

covalent, usually

Question 14

Why are covalent bonds strong?

Answer 14

As the shared electrons are attracted to the nucleus of both atoms

Question 15

Are multiple bonds or single bonds in covalent bonding stronger?

Answer 15

multiple bonds

Question 16

What is a dative covalent bond?

Answer 16

A covalent bond in which both electrons in the bond come from one atom

Question 17

Why do lone pairs repel more than bonding pairs?

Answer 17

as lone pairs are held closer to the nucleus of an atom, so they repel each other more as they are physically closer

Question 18

What is molecule geometry directed by?

Answer 18

electron repulsion

Question 19

What is the trend in repulsion strength of lone pairs and bonding pairs, from most to least?

Answer 19

1. Lone pair - Lone pair
2. Lone pair - Bonding pair
3. Bonding pair - bonding pair

Question 20

When will a molecule likely adopt a linear geometry?

Answer 20

if the central atom of a molecule has two electron bonding pairs

Question 21

What is the bond angle of a linear molecule?

Answer 21

180 degrees

Question 22

When will a molecule likely adopt a trigonal planar geometry?

Answer 22

if the central atom of a molecule has three bonding electron pairs

Question 23

What is the bond angle of a trigonal planar molecule?

Answer 23

120 degrees

Question 24

When will a molecule likely adopt a pyramidal geometry?

Answer 24

if the central atom has four electron pairs, where 3 of the four pairs are bonding pairs and 1 of the 4 pairs are lone pairs

Question 25

What is the bond angle of a pyramidal molecule?

Answer 25

107 degrees

Question 26

When will a molecule likely adopt a tetrahedral geometry?

Answer 26

if the central atom of a molecule has four bonding pairs of electrons

Question 27

What is the bond angle of a tetrahedral molecule?

Answer 27

109.5 degrees

Question 28

When will a molecule likely adopt an octahedral geometry?

Answer 28

if the central atom of a molecule has 6 bonding pairs of electrons

Question 29

What is the bond angle of an octahedral molecule?

Answer 29

90 degrees