Bonding and Properties

Question 1

When do changes of state occur?

Answer 1

In changes in temperature.

Question 2

What is the ionic charge of Group 1 elements?

Answer 2

Positive.

Question 3

What is the ionic charge of Group 2 elements?

Answer 3

Positive.

Question 4

What is the ionic charge of Group 3 elements?

Answer 4

Positive.

Question 5

What is the ionic charge of Group 6 elements?

Answer 5

Negative.

Question 6

What is the ionic charge of Group 7 elements?

Answer 6

Negative.

Question 7

What force holds ionic compounds together?

Answer 7

Strong electrostatic forces.

Question 8

What are the properties of ionic compounds?

Answer 8

They have high melting and boiling points, are hard and brittle, and conduct electricity when melted or dissolved in water, but not in the solid state.

Question 9

What are the five giant covalent structures?

Answer 9

Diamond, graphite, graphene, silicon dioxide and buckminster fullerene.

Question 10

What are the properties of graphite?

Answer 10

Each carbon atom bonds to three others and forms hexagonal rings in layers, which can slide over each other (so soft) and have one spare electron, which is delocalised and therefore free to move around the structure and it’s an electrical conductor.

Question 11

What are the properties of graphene?

Answer 11

It consists of only a single layer of graphite. Its strong covalent bonds make it a strong material that can also conduct electricity. It is also used in composites and high-tech electronics.

Question 12

What are the properties of fullerenes?

Answer 12

They are hollow cages of carbon atoms bonded together in one molecule and can be arranged as a sphere or a tube (called a nanotube). Molecules are held together by weak intermolecular forces so they can slide over each other, and they conduct electricity.

Question 13

What are the properties of fullerene spheres?

Answer 13

Buckminsterfullerene was the
first fullerene to be discovered and has 60 carbon atoms. Other fullerenes exist with different numbers of carbon atoms arranged in rings that form hollow shapes. Fullerenes like this can be used as lubricants and in drug delivery.

Question 14

What are the properties of fullerene nanotubes?

Answer 14

The carbon atoms are arranged in cylindrical tubes. Their high tensile strength (they are difficult to break when pulled) makes them useful in electronics.

Question 15

What are the properties of diamond?

Answer 15

It has exceptional hardness and high thermal conductivity, a high refractive index (making it very sparkly) and transparency. It also has a very high melting point due to its strong covalent bonds and each carbon atom bonds to four other carbon atoms.

Question 16

What are the properties of small covalent molecules?

Answer 16

They have weak intermolecular forces between molecules, meaning very little energy is needed to overcome forces. They have low melting and boiling temperatures and do not conduct as molecules have no charge.

Question 17

What are examples of small covalent molecules?

Answer 17

Carbon dioxide, ammonia, methane and silicone dioxide.

Question 18

What are the properties of giant covalent structures?

Answer 18

They have many, very strong covalent bonds, which need a lot of energy needed to overcome, therefore, very high melting and boiling temperatures. Only graphite, graphene and fullerenes will conduct electricity due to delocalised electrons that are free to move throughout the entire structure.

Question 19

What are the properties of ionic structures?

Answer 19

Thet have strong electrostatic forces between ions. A lot of energy is needed to overcome the forces, meaning high melting and boiling temperatures, and will only conduct when ions are free to flow in a liquid or aqueous.

Question 20

What is an ionic lattice?

Answer 20

Regular, three-dimensional arrangement of alternating positive and negative ions, held together by strong electrostatic forces (ionic bonds) in an ionic compound.

Question 21

What are the properties of metallic structures?

Answer 21

They have strong electrostatic forces, meaning a lot of energy is needed to overcome the forces meaning high melting and boiling temperatures. Electrons are free to move throughout the structure and carry charge. Metal layers can slide: malleable, but alloys have distorted layers: harder.

Question 22

What are the properties of polymers?

Answer 22

They have relatively strong intermolecular forces, so they are solids at room temperature. Thermosoftening polymers have no cross links, so they have a lower melting point and cross links between polymer chains, requiring more energy to overcome, so they have a higher melting point.

Question 23

What are polymers?

Answer 23

Large molecules made up of repeating units called monomers.

Question 24

How are metals bonded?

Answer 24

A positive metal nuclei, surrounded by a sea of delocalised electrons, is held together by strong electrostatic forces.

Question 25

How are particles arranged in solids?

Answer 25

There are strong forces between particles. They are closely packed and in fixed positions.

Question 26

How are particles arranged in liquids?

Answer 26

There are weaker forces between particles than solids, but they are touching and free to move.

Question 27

How are particles arranged in gases?

Answer 27

There are weaker forces between the particles and are spaced out.

Question 28

What are the limitations of the particle model?

Answer 28

All particles are represented as solid spheres. All particles are shown as the same size. There are no forces shown.

Question 29

What does aqueous mean?

Answer 29

A substance is dissolved in water

Question 30

What are the properties of ionic compounds?

Answer 30

Strong electrostatic forces between oppositely charged ions. Forces act in all directions in the lattice. A lot of energy is needed to overcome, meaning they have high melting and boiling points.

Question 31

In what state do substances conduct electricity?

Answer 31

Liquid and aqueous as the ions are free to move and carry charge.

Question 32

Why don't covalent molecules conduct electricity?

Answer 32

There are no charged particles to flow throughout the structure. Electrons are shared between atoms.

Question 33

Why are polymers solid at room temperature?

Answer 33

Intermolecular forces between polymer molecules are relatively strong, meaning a loy of energy is needed to overcome these forces.

Question 34

Why are metal alloys harder than pure metals?

Answer 34

Different sized atoms distort the layers of the metal ions, so layers are less able to slide over each other.

Question 35

Why are metals good conductors?

Answer 35

They have delocalised electrons that can carry a charge and flow throughout the entire structure.

Question 36

Why can graphite conduct electricity?

Answer 36

One electron from each carbon atom is delocalised and can flow throughout the entire structure.

Question 37

What does limiting reactant mean?

Answer 37

It will run out in the reaction.