Bonding

Question 1

What is ionic bonding?

Answer 1

Electrostatic forces of attraction between negative and positive ions.

Question 2

What is the structure of ionic compounds?

Answer 2

A giant ionic lattice made up of alternating positive and negative ions held together by electrostatic forces of attraction.

Question 3

Why can ionic compounds only conduct electricity when molten?

Answer 3

The ions are only free to move and carry charge when it is molten.

Question 4

Why do ionic compounds have high melting points?

Answer 4

They are held together by strong electrostatic forces of attraction that need a lot of energy to break.

Question 5

Why are ionic compounds soluble in water?

Answer 5

It is a polar compound meaning that the positive charges will be attracted to the slightly negative charge in the water and the negative charges will be attracted to the positive side of the water. The water surrounding the molecules is what makes them dissolve.

Question 6

What is covalent bonding?

Answer 6

The sharing of electrons between two non-metal atoms.

Question 7

Why do simple molecular substances have low melting and boiling points?

Answer 7

The intermolecular forces that hold the molecules together are weak and don’t need much energy to break.

Question 8

What is the structure of macromolecular substances?

Answer 8

They are giant covalent structures.

Question 9

Why is graphite soft?

Question 10

Why can graphite conduct electricity?

Question 11

Why does graphene have a higher melting point compared to graphite?

Question 12

Why does a diamond have a high melting point?

Question 13

Why does a diamond not conduct electricity?

Question 14

What is a dative covalent bond?

Question 15

What is the VSEPT theory?

Answer 15

Lone pairs repel more than bond pairs so bond angles are often reduced because the bond pairs are often pushed together by lone-pair repulsion.

Question 16

Go over bond angles.

Question 17

What is electronegativity?

Answer 17

The ability of an atom to attract the pair of electrons that make up a covalent bond.

Question 18

Why are the covalent bonds in diatomic gases non-polar?

Question 19

Why is the bond in HCl polar?

Answer 19

The chlorine is more electronegative meaning it will attract the pair of electrons in the covalent bond towards it and away from the hydrogen. This gives it a slightly negative charge and hydrogen a slightly positive charge.

Question 20

What are the other names for van der Waals forces?

Answer 20

1. London dispersion forces
2. Induced dipole-dipole forces.

Question 21

How do van der Waals forces form?

Answer 21

When the electrons in an atom randomly shift to one side this forms a spontaneous dipole. This dipole then pushes the electrons of the atoms near it to one side and this creates an induced dipole. The two dipoles are attracted to each other and this is what created the van der Waals forces.

Question 22

What two factors affect the strength of the van der Waals forces?

Answer 22

The bigger the molecule is the bigger the van der Waals forces as they have more electrons. The closer together the molecules are the stronger the van der Waals forces.

Question 23

How do permanent dipole-dipole forces form?

Answer 23

There will be weak electrostatic forces of attraction between the positive and negative ends of permanent dipoles.

Question 24

What factors affect the strength of permanent dipole-dipole forces?

Answer 24

The bigger the difference in polarity the stronger the forces are.

Question 25

What is hydrogen bonding?

Answer 25

When hydrogen is bonded to fluorine, nitrogen, or oxygen it will form weak bonds with the other fluorine, nitrogen, or oxygen next to it.

Question 26

Why does water have a higher boiling point compared to hydrogen sulfide?

Answer 26

There are hydrogen bonds between the molecules of water and permanent dipole-dipole forces between the molecules of hydrogen sulfide. The hydrogen bonds are much stronger meaning they need more energy to break.

Question 27

Why is ice less dense compared to liquid water?

Answer 27

The oxygen in water bonds to two hydrogen atoms and two other water molecules. The fact that it has a tetrahedral shape means that when water is frozen the molecules spread as far away from each other as they can and this increases the volume of the water. The increase in volume leads to a decrease in density.

Question 28

What is metallic bonding?

Answer 28

The electrostatic forces of attraction between the positive ions and delocalised electrons.

Question 29

Why do metals have high boiling points?

Answer 29

They are held together by strong electrostatic forces of attraction that need a low of energy to break.

Question 30

What factors affect how strong the metallic bonds are?

Answer 30

1. The smaller the positive ions the stronger the electrostatic forces of attraction will be.
2. The higher the positive charge is the stronger the electrostatic forces of attraction because there are more delocalized electrons.

Question 31

Why are metals malleable?

Answer 31

Since no bonds are holding the positive ions together they can slide over each other.

Question 32

Why can metals conduct electricity?

Answer 32

The delocalized electrons are free to move and carry charge.

Question 33

Why are metals insoluble?

Answer 33

The metallic bonds need a lot of energy to break.