Key Concepts

Question 1

Water Equation

Answer 1

H20

Question 2

Carbon Dioxide equation

Answer 2

C02

Question 3

Chlorine equation

Answer 3

Cl2

Question 4

Ammonia equation

Answer 4

NH3

Question 5

Hydrogen equation

Answer 5

H2

Question 6

Oxygen equation

Answer 6

O2

Question 7

Ammonium ion equation

Answer 7

NH4+

Question 8

Nitrate ion equation

Answer 8

NO3-

Question 9

Sulfate ion equation

Answer 9

SO4 2-

Question 10

Hydroxide ion equation

Answer 10

OH-

Question 11

Carbonate ion equation

Answer 11

CO3 2-

Question 12

What does oxidising symbol mean

Answer 12

Provides oxygen which allows other materials to burn better

Question 13

What does harmful symbol mean

Answer 13

Can cause irritation and blistering of skin

Question 14

What dies toxic symbol mean

Answer 14

Can cause death by inhaling or taking in

Question 15

What does corrosive sign mean

Answer 15

Destroys materials and living tissue

Question 16

What did John dalton show an atom as

Answer 16

A solid sphere and that different spheres make different elements

Question 17

What did jj thomson say about the atom

Answer 17

Atoms weren’t solid spheres and that charge and mass showed that an atom must contain smaller negatively charged particles called electrons. Called plum pudding

Question 18

What did rutherford say about the atom

Answer 18

Gold foil experiment
Fired positive charged alpha particles at thin sheet of gold. Expected particles to go straight through but some wer deflected more than expected and some deflected backwards. Came up with idea of the nucleus

Question 19

What did bohr say about the atom

Answer 19

The electrons are contained in shells that only exist in fixed orbits. Each shell has fixed energy

Question 20

What does the nucleus of an atom contain

Answer 20

Protons and neutrons. Positive charge. Whole mass is concentrated in neucleus

Question 21

What does size of electron shell show.

Answer 21

The size of the atom

Question 22

What does atomic number show

Answer 22

How many protons. Bottom left.

Question 23

What does mass number show

Answer 23

Total number of protons and neutrons in atom

Question 24

What is number of protons equal to

Answer 24

Number of electrons

Question 25

What are isotopes

Answer 25

Different forms of the same element which have same number of protons but different number of neutrons

Question 26

How many electrons allowed in first shell

Answer 26

2

Question 27

How many electrons allowed in second and third shell

Answer 27

8

Question 28

What are ions

Answer 28

Charged particles. Happens when an atom loses or gains an electron to form ions. Trying to get full outer shell.

Question 29

What is anion

Answer 29

When atoms gain electrons. More electrons than protons

Question 30

What is cation

Answer 30

When atoms lose electrons - more protons than electrons

Question 31

How do you find charge of ion

Answer 31

The number of electrons lost or gained

Question 32

What is the overall charge of an ionic compound

Answer 32

0

Question 33

Properties of ionic compounds

Answer 33

High melting and boiling points as strong attraction between ions Dont conduct electricity, however when melted can carry electric current Dissolve easily in water, will carry an electric current in liquid

Question 34

What is a covalent bond

Answer 34

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

Question 35

How are simple molecular substances made

Answer 35

Made of molecules containing few atoms joined by covalent bonds. Use dot and cross diagrams to show

Question 36

Properties of simple molecular substances

Answer 36

Atoms within molecules held together by very strong covalent bonds Forces of attraction between molecules very weak Melting and boiling points low as easily separated Usually gases or liquid at room temp As molecules get bigger intermolecular forces get stronger Dont conduct electricity

Question 37

What is a polymer

Answer 37

Molecules made of long chains of covalently bonded carbon atoms

Question 38

Properties of giant covalent structure

Answer 38

All atoms bonded together by strong covalent bonds Very high melting and boiling points Dont conduct electricity Not soluble in water

Question 39

What are fullerenes

Answer 39

Molecule of carbon shaped like closed tubes. Made of carbon atoms arranged in hexagons or pentagons

Question 40

How are metals bonded

Answer 40

Have giant structure. Electrons on outer shell are delocalised. Strong forces of electrostatic attraction between positive metal ions and electrons. Forces of attraction hold atoms together in regular structure known as metallic bonding. Very strong Compounds include alloys and metallic elements

Question 41

Properties of metals

Answer 41

``` Hard to break High melting and boiling points Usually shiny solids at room temp Not soluble in water More dense than non metals Malleable Good conductors of electricity and heat ```

Question 42

What happens to mass in chemical reaction

Answer 42

No atoms destroyed or created