Chemistry Y9

Question 1

What is an isotope?

Answer 1

Atoms of the same element and same number of protons but different number of neutrons

Question 2

How many electrons would be in the outer shell of an element in group 7?

Answer 2

7 electrons in the outer shell

Question 3

What is a molecule?

Answer 3

Two or more atoms of the same or different elements chemically bonded

Question 4

Why is rubidium more reactive than potassium?

Answer 4

Rubidium is larger so the negative outer shell of electrons is further away from the positive nucleus. Therefore the electrostatic attractions weakens so its easier to lose electrons- therefore it’s more reactive

Question 5

What did Rutherford conclude in the Alpha Scattering experiment?

Answer 5

Most of the particles went through - mostly empty space

Some were repelled - repelled by something positive

Some rebounded fully - Hit something small, dense and positive (nucleus)

Question 6

What is the mass of protons, neutrons and electrons

Answer 6

Proton: 1
Neutron: 1
Electron: 0

Question 7

What are the charges of electrons, protons and neutrons?

Answer 7

Proton: positively charged
Electron: negatively charged
Neutron: no charge

Question 8

What is solubility?

Answer 8

A measure of how much a substance dissolves

Question 9

What is a solvent?

Answer 9

A liquid that dissolves a substance

Question 10

What is a solution?

Answer 10

Formed when a solid dissolves in a liquid

Question 11

What is a solute?

Answer 11

A substance that dissolves in a liquid

Question 12

What is retention Factor (Rf)

Answer 12

Measure of solubility

Question 13

What is the law of the conservation of mass?

Answer 13

Mass of reactants = Mass of products
(No mass added or removed)
Exception:
If one of the reactants or one of the products is a gas then mass can appear to be gained or lost.

Question 14

What are the properties of the transitional metals?

Answer 14

hard and strong
high melting and boiling point
form multiple ions
for coloured compounds
7 electrons in outer shell (group 7)
shiny
ductile
malleable
sononrous
central in the periodic table

Question 15

What are the properties of the alkali metals?

Answer 15

soft to cut
low melting and boiling points
more reactive going down group
one electron in outer shell (group 1)
ductile
shiny
malleable
sonorous
metal

Question 16

Properties of metals

Answer 16

Hard / strong
Conduct heat / electricity
High mpts
Malleable

Question 17

What are the giant covalent structures?

Answer 17

Diamond (SiO2)
Graphite
Graphene
Fullerene
Nanotube

Question 18

Metal + oxygen = ?

Answer 18

Metal oxide

Question 19

Metal + water =

Answer 19

Metal hydroxide + hydrogen

Question 20

Metal + acid = ?

Answer 20

Metal salt + hydrogen

Question 21

Properties of giant covalent structures?

Answer 21

High mpt + bpt (strong covalent bonds = lots of energy to overcome)
Hard and strong (e.g diamond)
Insoluble in water

Question 22

What is an alloy?

Answer 22

Mixture (not bonded) of two or more elements, at least one of which is a metal

Question 23

Why are alloys harder than pure metals?

Answer 23

Different sizes atoms disrupt the regular crystal lattice structure of a metal so the layers can no longer slide and the structure becomes harder

Question 24

How are covalent bonds formed?

Answer 24

By atoms sharing electrons

Question 25

Why do giant covalent structures have high melting points?

Answer 25

It takes a lot of energy to break the strong covalent bonds between the atoms

Question 26

Why does graphite conduct electricity?

Answer 26

The delocalized electrons can move through the graphite

Question 27

Explain why graphite is soft

Answer 27

Layers do not have strong covalent bonds so can slide over each other

Question 28

Give two properties of graphene

Answer 28

Strong Conducts electricity

Question 29

Give two properties of nanotubes

Answer 29

High tensile strength Conduct electricity

Question 30

Why do small covalent molecules have low melting points?

Answer 30

Only a small amount of energy is needed to overcome the weak intermolecular forces

Question 31

Describe the structure and bonding of polymers

Answer 31

Many identical molecules joined together by strong covalent bonds in a long chain, with weak intermolecular forces between the chains

Question 32

Why do ionic substances have high melting and boiling points?

Answer 32

Electrostatic attraction between positive metal ions and negative non metal ions is strong and requires lots of energy to overcome

Question 33

Properties of pure metals

Answer 33

Malleable High melting + boiling points Conduct electricity Conduct thermal energy

Question 34

Why are alloys harder than pure metals

Answer 34

Different sizes atoms disturb the layers, preventing them from sliding over eachother