Key Concepts in Chemistry

Question 1

What is the Atom?

Answer 1

All substances are made of atoms.
Atoms are made up of 3 subatomic particles, Protons, Neutrons and Electrons.

Question 2

What is a Proton?

Answer 2

Relative charge: +1
Relative mass: 1
It is located in the Nucleus.

Question 3

What is a Neutron?

Answer 3

Relative charge: 0
Relative mass: 1
It is located in the Nucleus.

Question 4

What is an Electron?

Answer 4

Relative charge: -1
Relative mass: 0.0005
It moves around the Nucleus in electron shells.

Question 5

Atoms have the same number of:

Answer 5

Protons and Electrons.

Question 6

What describes an Atom?

Answer 6

Its Atomic Number and Mass Number.

Question 7

What does the Atomic number tell you?

Answer 7

it tells you how many protons an atom has.

Question 8

What does the Mass number tell you?

Answer 8

total number of protons and neutrons in an atom.

Question 9

What are Isotopes?

Answer 9

different forms of the same element, which have the same number of protons but a different number of neutrons.

Question 10

What is the Relative Atomic Mass?

Answer 10

the average mass of one atom of the element, compared to 1/12 of the mass of one atom of carbon-12.

Question 11

What is the Formula to work out the Relative atomic mass?

Answer 11

Relative Atomic Mass = sum of (isotope abundance * isotope mass number) / sum of abundances of all the isotopes.

Question 12

What are Ions?

Answer 12

Charged particles - they can be single atoms or groups of atoms, its when atoms lose or gain electrons.

Question 13

How do negative Ions (anions) form?

Answer 13

when atoms gain electrons.

Question 14

How do Positive Ions (cations) form?

Answer 14

when atoms lose electrons.

Question 15

What Groups in the periodic table are most likely to form Ions?

Answer 15

Groups 1,2, 6 and 7.

Question 16

How many Electrons can go in the 1st shell?

Answer 16

2 electrons

Question 17

How many Electrons can go in the 2nd and 3rd shell?

Answer 17

8 electrons

Question 18

What happens when a Metal and Non-metal react?

Answer 18

Metal atoms lose electrons to become positively charged ion
Non-metals gain electrons to become negatively charged ion

Question 19

What is an Ionic bond?

Answer 19

When oppositely charged ions are strongly attracted to one another by electrostatic forces.

Question 20

What is the structure of a Ionic Compound called?

Answer 20

Regular Lattice Structure

Question 21

What are the 2 types of models on Ionic Compounds?

Answer 21

2D model, Ball and stick

Question 22

What is a Covalent Bond?

Answer 22

a strong bond that forms when a pair of electrons is shared between 2 atoms.

Question 23

What are the properties of a Simple Molecular Substance?

Answer 23

Usually have Simple molecular structures
Very strong covalent bonds
Forces of attraction between these molecules are very weak
Don’t conduct electricity
Some soluble some aren’t

Question 24

How do all the atoms in giant covalent structures bond to each other?

Answer 24

by strong covalent bonds

Question 25

Do giant covalent bonds have a high or low melting and boiling point?

Answer 25

High, lots of energy is needed to break down the covalent bonds

Question 26

Are giant covalent structures soluble in water?

Answer 26

No

Question 27

What is diamond made up of?

Answer 27

a network of carbon atoms that each form four covalent bonds.

Question 28

What are the properties of diamond?

Answer 28

has a high melting point
rigid lattice structure
doesn’t conduct electricity because it has no free electrons or ions

Question 29

Properties of Graphites?

Answer 29

each carbon atom only forms three covalent bonds, creating sheets of carbon atoms arranged in hexagons
aren’t any covalent bonds between the layers.
makes graphite soft and slippery, so it’s ideal as a lubricating material.
High melting point
Conducts electricity as there is a delocalised electron.

Question 30

What is Graphene?

Answer 30

one layer of graphite
sheet of carbon atoms joined together in hexagons
sheet is just one atom thick, making it a two-dimensional substance

Question 31

What are fullerenes?

Answer 31

molecules of carbon shaped like closed tubes or hollow balls.
mainly made up of carbon atoms arranged in hexagons.
can be used to cage other molecules
deliver a drug
huge surface area, help make great industrial catalysts.

Question 32

How does Metallic bonding involve delocalised electrons?

Answer 32

There are strong forces of electrostatic attraction between the positive metal ions and the shared negative electrons.
these forces of attraction hold the atoms together in a regular structure and are known as metallic bonding.

Question 33

Physical properties of Metals?

Answer 33

Lots of energy needed to break, forces between metal ions and delocalised electrons are very strong.
high melting and boiling point
aren’t soluble in water
more dense than non metals
malleable
good conductors of heat and electricity

Question 34

What is the rule during a chemical reaction?

Answer 34

no atoms are destroyed an no atoms are created.
This means there are the same number and types of atoms on each side of a reaction equation.

Question 35

What does it mean if the mass seems to change?

Answer 35

usually a gas involved