Atomic Structure and Covalent Bonding

Question 1

What is meant by the term Isotope.

Answer 1

An isotope is an atom with the same atomic number but different mass number.

Question 2

What is meant by the term relative atomic Mass?

Answer 2

The relative atomic mass is the calculation used to find the weighted average mass between two or more isotopes, using the abundance percentage X the atomic number.

Question 3

What is meant by the term covalent bond?

Answer 3

A covalent bond is the force of attraction between a shared pair of electrons and nuclei.

Question 4

What are simple Molecular structures?

Answer 4

Covalently bonded molecules with weak intermolecular forces.

Question 5

Give two examples of substances with Giant covalent structures?

Answer 5

Diamond and Graphite

Question 6

Why do Giant covalent substances have high melting points?

Answer 6

They have a lot of very strong covalent bonds and it takes a huge amount of energy to break the bonds.

Question 7

Explain in terms of its structure why graphite is used as a lubricant?

Answer 7

Graphite is made up of layers of carbon. Graphite is very slippery and the layers separate very easily because of weak forces of attraction. As it is slippery it makes a good lubricant.

Question 8

In terms of its structure why is diamond used in cutting?

Answer 8

Diamond is made up of lots of covalent bonds which require a lot of energy to break. it is a giant interlocking molecular structure and is an very hard substance.

Question 9

What is an atom?

Answer 9

A single particle (no charge)

Question 10

What is a molecule?

Answer 10

two or more atoms chemically joined together

Question 11

what is an ion?

Answer 11

a charged particle

Question 12

What is an element?

Answer 12

A collection of atoms or molecules of the same kind.

Question 13

what is a compound?

Answer 13

Two or more elements chemically combined.

Question 14

what is a mixture?

Answer 14

different elements or compounds mixed together.

Question 15

what is the structure of an atom?

Answer 15

the atom is made up of a central nucleus surrounded by electron shells.

Question 16

What are the three sub-atomic particles an atom is made up of?

Answer 16

Protons neutrons electrons

Question 17

What is an atomic number?

Answer 17

Is the number of protons in the nucleus of an atom

Question 18

What is the mass number?

Answer 18

the sum of the number of protons and neutrons in the nucleus of the atom.

Question 19

Nuetral atoms have what kind of charge?

Answer 19

zero charge

Question 20

What is a charged atom called?

Answer 20

an ion

Question 21

If an electron is added to a neutral atom what kind of charge does it gain?

Answer 21

It becomes negatively charged.

Question 22

A covalent bond is usually formed between what?

Answer 22

Two non-metals

Question 23

the sharing of electrons results in what?

Answer 23

both atoms having a complete outer shell of electrons.

Question 24

what does a full shell mean?

Answer 24

the arrangement is particularly stable

Question 25

covalent bonds are?

Answer 25

very strong and require a lot of energy to break.

Question 26

Covalently substances can form two types of structures:

Answer 26

Simple molecular giant covalent

Question 27

what is a molecule?

Answer 27

A small group of atoms joined by covalent bonds

Question 28

3 molecular elements include:

Answer 28

oxygen, hydrogen, nitrogen

Question 29

3 molecular compounds include:

Answer 29

Carbon Dioxide, water, methene

Question 30

Properties of simple molecular substances include:

Answer 30

They can be solids, liquids or gases, they have low melting and boiling points

Question 31

why do simple molecular substances have low melting points?

Answer 31

-Weak forces of attraction -wear intermolecular forces do not require a lot of energy to break

Question 32

Giant covalent substances include:

Answer 32

diamond (carbon atoms) graphite (carbon atoms) sand (silicon dioxide)

Question 33

diamond has what kind of melting points and why?

Answer 33

very high melting points because it has very strong covalent bonds

Question 34

In what way is Graphite arranged?

Answer 34

In layers of hexagons-strong covalent bonds join atoms together. layers need a lot of energy to break.

Question 35

What is between the layers in graphite?

Answer 35

Weak forces of attraction

Question 36

Does Graphite conduct electricity and why?

Answer 36

Yes, because it has delocalised electrons which can carry a current.

Question 37

How is sand (silicon dioxide) structured?

Answer 37

Each silicon atom is covalently bonded to 4 oxygen atoms and each oxygen is covalently bonded to two silicon atoms. No delocalised electrons

Question 38

Describe the structure of diamon

Answer 38

Question 39

describe the structure of Graphite?

Answer 39

Question 40

Describe the structure of sand

Answer 40