Chemistry Section 1 & 2

Question 1

Define what a compound is

Answer 1

Two or more elements Chemically combined

Question 2

Define what a mixture is

Answer 2

Two or more substances in any quantity

Question 3

Define what relative atomic mass is

Answer 3

An average of the atomic masses of all the isotopes of an element taking into account the relative abundances/percentage of each isotope

Question 4

How are elements arranged in the periodic table

Answer 4

In order of reactivity

Question 5

Why do elements in the same group of the periodic table have similar chemical properties

Answer 5

They have the same number of electrons on the outer shell

Question 6

The elements in group 0 are known as the:

Answer 6

Noble gasses

Question 7

The elements in group 1 are known as the:

Answer 7

Alkali Metals

Question 8

The elements in group 7 are known as the:

Answer 8

Halogens

Question 9

What is an atom

Answer 9

The smallest part of an element that can exist

Question 10

What is on the left and right of a chemical equation?

Answer 10

Left: reactants Right: products

Question 11

How is an element different to a compound

Answer 11

A compound

Question 12

What is the equation for Neutrons?

Answer 12

Number of neutrons = mass number - atomic number

Question 13

How are the groups arranged?

Answer 13

By number of electrons on the outer shell: 1 electron = group 1

Question 14

Do melting and boiling points increase or decrease down the alkali metals?

Answer 14

Decrease

Question 15

What does aqueous mean (aq)

Answer 15

Dissolved in water

Question 16

What are the three types of strong chemical bonds

Answer 16

Ionic bonds, covalent bonds, metallic bonds

Question 17

Atoms that have gained or lost electrons are called:

Answer 17

Ions

Question 18

Ionic bonds occur between:

Answer 18

Positive and negative ions

Question 19

Ions have a:

Answer 19

complete outer shell of electrons

Question 20

Ionic bonding involves a transfer of electrons from:

Answer 20

Metal atoms to non-metal atoms

Question 21

The ionic bond is a strong ——- force of attraction between the positive metal ion and the negative non-metal ion

Answer 21

Electrostatic

Question 22

Describe what happens when two atoms of sodium react with one molecule of chlorine

Answer 22

Sodium (Group1)
Chlorine (Group7) has 2 atoms in a molecule.
The two atoms of sodium each give one electron from their outer shells, completing the 7/8 outer shells of the chlorine.
All 4 atoms now have 8 electrons in their outer shells.
The atoms become ions, Na+ and Cl-, the compound formed is sodium chloride, NaCl

Question 23

A covalent bond is a:

Answer 23

shared pair of electrons between atoms.

Question 24

covalent bonds occur in:

Answer 24

Non metallic elements, eg oxygen
Compounds of non metals, eg sulfur dioxide

Question 25

Small molecules have weak ——– forces of attraction

Answer 25

Intermolecular

Question 26

Substances that consist of small molecules usually have low ————————–

Answer 26

Melting and boiling points

Question 27

All the atoms in giant covalent structures are linked by ———————-

Answer 27

Strong covalent bonds

Question 28

Why does Hydrogen chloride have a low boiling point

Answer 28

Although there is a strong covalent bond within the molecule, there are only weak intermolecular forces between molecules

Question 29

Describe the structure of diamond

Answer 29

-It has a giant rigid covalent structure
-Each carbon atom forms four strong covalent bonds with other carbon atoms
-All the strong covalent bonds mean that it is a very hard substance with a very high melting point

Question 29

Explain how graphite can conduct electricity

Answer 29

One electron from each carbon atom in graphite is delocalised, these delocalised electrons allow graphite to conduct heat and electricity

Question 29

How does the size of a small molecule affect the strength of the intermolecular forces between molecules

Answer 29

The bigger the molecule, the larger the intermolecular forces

Question 29

Alkanes contain atoms of which two elements

Answer 29

Carbon and Hydrogen

Question 29

Which is weak in small molecules, intermolecular bonds or covalent bonds

Answer 29

Intermolecular

Question 29

Explain why diamond is hard

Answer 29

Because there are strong covalent bonds in between all the carbon atoms

Question 29

Explain why graphite can conduct electricity

Answer 29

Because there are delocalised electrons between the layers which can carry charge

Question 30

What is graphene

Answer 30

A single layer of graphite

Question 30

State some properties of graphene

Answer 30

It is very strong, a good thermal and electrical conductor and nearly transparent

Question 31

What is a metallic bond

Answer 31

A metallic bond is the attraction between the positive ions and the delocalised negatively charged electrons

Question 31

Why is copper a good material for water pipes

Answer 31

Because it is unreactive and is easily shaped