Structure and Bonding

Question 1

What is Ionic Bonding?

Answer 1

Between a metal and a non-metal
Metal lose electrons and become positive ions
Non-metals gain electrons and become negative ion
Positive and negative ions attract forming a strong ionic bond

Question 2

What is a Covalent bond?

Answer 2

Between two or more non-metals
Sharing of electrons
Covalent bonds are strong

Question 3

What are isotopes?

Answer 3

Isotopes always have the same number of protons but different number of neutrons.

Question 4

What type of bond is a Magnesium Oxide.

Answer 4

Ionic bond
Magnesium loses two electrons, giving them to oxygen
Oxygen gains two electrons
Ratio is one Mg²+ ion to one O²- ion
The Mg²+ ions and O²- ion attract to form an ionic bond.

Question 5

Why do you need a high temperature to melt potassium chloride?

Answer 5

Giant ionic lattice
Strong electrostatic forces of attraction between the k+ and Cl- ions.
Large amount of energy needed to break the strong bonds.

Question 6

Why doesn’t carbon dioxide conduct electricity?

Answer 6

Doesn’t conduct electricity because no charged particles (ions or free electrons).

Question 7

Why does sulfur dioxide have a low boiling point?

Answer 7

Simple covalent molecule
Weak inter molecular forces between the molecules.
Not much energy needed to break the forces.

Question 8

What are the properties of Chlorine?

Answer 8

Covalent bond

Each chlorine atom shares one electron to get a full outer shell.

Question 9

What are the properties of Diamond?

Answer 9

Diamond is hard because giant covalent structure

Each carbon is bonded to 4 other carbons with strong covalent bond.

Question 10

Why is graphite softer than diamond?

Answer 10

Graphite is softer than diamond because each carbon is bonded to 3 other carbon atoms (diamond is bonded to 4) so forms layers. Weak inter molecular forces between the layers.

Question 11

Why can graphite conduct electricity?

Answer 11

Each carbon is bonded to 3 other carbon atoms.
Each carbon atom has one delocalised electron
Delocalised electrons move through the graphite carrying the electric charge.

Question 12

Why is Silicon Dioxide hard and why does it have a high melting point?

Answer 12

It is a giant covalent structure
Each atom is bonded to many other atoms with strong covalent bonds
This means it is hard
Lots of energy need to break the strong bonds so it has a high melting point

Question 13

What is a fullerene?

Answer 13

Molecules of carbon atoms with hollow shapes. Fullerenes are based on hexagonal rings of carbon atoms(or ring with 5 or 7)

Question 14

What is Buckminsterfullerene?

Answer 14

The first fullerene to be discovered. It has 60 carbon atoms and a spherical shape.

Question 15

What is graphene?

Answer 15

A single layer of graphite useful for electronics and

composites.

Question 16

Why is graphene strong?

Answer 16

• Each carbon is bonded to 3 other carbon with
strong covalent bonds
• Only one atom layer thick (so no weak
intermolecular forces)

Question 17

What is nanoscience? (DON’T NEED)

Answer 17

Science of structures between 1-100nm in size (few

hundred atoms)

Question 18

State uses of nanoparticles (DON’T NEED)

Answer 18

• Cosmetics and sun cream
• Medicine
• Deodorants
• Electronics
• Catalysts

Question 19

State the size of different types of particles (DON’T NEED)

Answer 19

Fine particles (PM 2.5 ) – diameter 100-2500nm
Coarse particles (dust) (PM 10 ) – diameter 1x10 -5 m and 2.5x10 -6 m

Question 20

How does the size of a cube relate to the surface area to volume ratio? (DON’T NEED)

Answer 20

As the size of the cube decreases by a factor of 10 the

surface area to volume ratio increases by a factor of 10.

Question 21

Why do nanoparticles have different properties to the same material in bulk? (DON’T NEED)

Answer 21

Because of their high surface area to volume ratio.

Question 22

What are the possible risk of nanoparticles? (DON’T NEED)

Answer 22

Very reactive so risk of explosion for some substances
Could easily penetrate the human body
Could escape into the environment

Question 23

Describe the structure and bonding of metals.

Answer 23

• Layers of positive ions
• Outer shell of electrons is delocalised
• Positive ions attracted to the sea of electrons
forming a metallic bond
• Share delocalised electrons

Question 24

Explain why metals conduct electricity

Answer 24

• Outer shell of electrons is delocalised

Question 25

Explain why alloys are harder than pure metals.

Answer 25

• Pure metals, atoms in layers and can slide over
each other
• Alloys different sized atoms so not in layers so
cannot slide over each other

Question 26

What are carbon nanotubes?

Answer 26

Cylindrical fullerenes with high length to diameter ratio. They are useful for nano technology electronics and materials.