Bonding

Question 1

What are the 3 types of strong chemical bonds?

Answer 1

Ionic, covalent, metallic

Question 2

What is ionic bonding?

Answer 2

Involves electrostatic attraction between oppositely charged ions in a lattice

Question 3

What are properties of ionically bonded compounds?

Answer 3

They are always solids at room temperature
They have giant structures, and therefore high melting points
They conduct electricity when molten or dissolved in water, but not when solid
They are brittle and shatter easily

Question 4

Why do ionic compounds shatter easily?

Answer 4

As they form a lattice of alternating positive and negative ions, a blow may move the ions and produce contact with ions of like charges

Question 5

What is covalent bonding?

Answer 5

A bond formed between a pair of non-metal atoms, where an electron is shared, so that each atom can achieve a stable noble gas arrangement

Question 6

Are covalent bonds stronger than ionic bonds?

Answer 6

They are equally strong

Question 7

What are some properties of covalent molecules?

Answer 7

They have low melting and boiling points, they are poor conductors of electricity, even when dissolved in water

Question 8

What is a dative covalent bond?

Answer 8

Covalent bonding in which both the electrons in the bond come from one of the atoms in the bond

Question 9

What is metallic bonding?

Answer 9

It involves the attraction between delocalised electrons and positive ions arranged in a lattice

Question 10

What are some properties of metals

Answer 10

Good conductors of electricity, they are strong, they are malleable, ductile and have high melting points

Question 11

What does malleable mean?

Answer 11

They can be beaten into shape

Question 12

What does ductile mean?

Answer 12

They can be pulled into thin wires

Question 13

What are the four types of crystal structures?

Answer 13

Ionic, metallic, macromolecular, molecular

Question 14

Give two examples of a macromolecular crystal

Answer 14

Diamond, graphite

Question 15

Give 2 examples of molecular crystal

Answer 15

Ice, iodine

Question 16

Give example of metallic crystal

Answer 16

Magnesium

Question 17

Give example of ionic crystal

Answer 17

Sodium chloride

Question 18

How many bonds does each carbon form in diamond?

Answer 18

4 single covalent bonds

Question 19

Can diamond conduct electricity? Why?

Answer 19

No, as it doesn’t have any free electrons in its structure

Question 20

How many bonds does each carbon form in graphite?

Answer 20

3 single covalent bonds

Question 21

Can graphite conduct electricity? Why?

Answer 21

Yes, as it has delocalised electrons in its structure that are free to carry charge

Question 22

How does electron repulsion affect the shape of molecules?

Answer 22

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

Question 23

What is shape, name and bond angle of molecule with 2 bonding pairs?

Answer 23

linear, 180

Question 24

What is shape, name and bond angle of molecule with 3 bonding pairs?

Answer 24

trigonal planar, 120

Question 25

What is shape, name and bond angle of molecule with 4 bonding pairs?

Answer 25

tetrahedral, 109.5

Question 26

What is shape, name and bond angle of molecule with 5 bonding pairs?

Answer 26

trigonal bipyramidal, 120 and 90

Question 27

What is shape, name and bond angle of molecule with 6 bonding pairs?

Answer 27

octahedral, 90

Question 28

What is shape, name and bond angle of molecule with 1 lone pair and 3 bonding pairs?

Answer 28

triangular pyramidal, 107

Question 29

What is shape, name and bond angle of molecule with 2 lone pairs and 2 bonding pairs?

Answer 29

bent, 104.5

Question 30

What is shape, name and bond angle of molecule with 2 lone pairs and 4 bonding pairs?

Answer 30

square planar, 90

Question 31

Define electronegativity

Answer 31

The power of an atom to attract the pair of electrons in a covalent bond towards itself

Question 32

How does a polar covalent bond come about?

Answer 32

The electron distribution in a covalent bond between elements with different electronegativities will be unsymmetrical.

Question 33

What are the 3 types of intermolecular forces?

Answer 33

Permanent dipole-dipole forces, van der Waals forces, hydrogen bonding

Question 34

Why is hydrogen bonding so important in ice?

Answer 34

When water is liquid, h bonds break and form easily, as molecules move about. When water freezes, , molecules no longer able to move freely about - h bonds hold them in fixed positions to fit this structure, molecules are slightly less closely packed than in water, so ice has lower density than water

Question 35

What are van der Waals forces?

Answer 35

At any point, the electron density of an atom can shift to one side and form partial charges. The partial positive charge on one side of the molecule approaches another molecule, and attracts the electrons of that molecules towards itself, inducing dipoles on this molecule. There is attraction between partial positive charge on one molecule and the partial negative on another

Question 36

For what kind of molecules do van der Waals forces form?

Answer 36

all molecules

Question 37

How do dipole-dipole forces form?

Answer 37

All molecules with polar bonds have dipole dipole forces

Question 38

For which molecules do dipole dipole forces form?

Answer 38

Only molecules that have permanent dipoles

Question 39

How do hydrogen bonds form?

Answer 39

When a hydrogen atoms is bonded to a very electronegative atom, a strong partial positive charge is produced. This partial positive charge comes across another very electronegative molecule with a lone pair of electrons, and they are attracted towards each other

Question 40

For which molecules do hydrogen bonds form?

Answer 40

between Hydrogen and Oxygen, Nitrogen and Fluorine