Chemistry Paper 1

what is an atom?

The smallest part of an element

What is the plum pudding mode of the atom?

A positive sphere with negative electrons inside it

What is the relative charge of each subatomic particle?

Proton = positive | neutron = neutral | electron = negative

How can you find the number of protons in an atom? How to calculate the number of neutrons?

• atomic number

• Atomic mass - atomic number

What is a compound?

Where 2 or more different elements have been chemically combined

Draw the nuclear model of the atom & the modern atom

(Insert photo)

What did James Chadwick discover?

Neutrons

What is the relative atomic mass of each particle?

Proton and neutron = 1 | electron = 1/2000

Why do atoms have no overall charge?

They have the same number of protons(+ve) and electrons(-ve) which cancel each other out

What is an element?

A substance which contains only one type of atom

What is a mixture?

Where 2 or more different elements have NOT been chemically combined

What are isotopes?

The same type of atom which has the same number of protons and electrons but different number of neutrons

List the physical processes which can be used to separate mixtures

Filtration, crystallisation, chromatography, distillation, evaporation, sieving

How are covalent bonds formed? What type of atoms form covalent bonds?

• Pair and share of electrons

• Non metals

Describe the structure and bonding of a giant covalent substance

Strong lattice of carbon bonds (e.g. diamond or graphite), very large number of carbon bonds

Describe the structure and bonding of a small molecule

Gas, 2 nonmetals bonded by covalent bonds, carbon dioxide, methane(?)(CH4)

Why do giant covalent substances have high melting points?

They have lots of energy so they have strong intermolecular forces

Why do small substances have low melting points?

They receive low energy so they have weak intermolecular forces

Why do large molecules have higher melting and boiling points than small molecules?

they need more energy to break bonds

What kind of elements form ionic bonds?

Metals and non-metals

What charges group 1&2 form and 6&7 form

• Positive

• Negative

Name the force which holds oppositely charged ions together

Electrostatic

Describe the structure of a giant ionic lattice

Held together in a regular structure of +ve and -ve ions

Why don’t ionic substances conduct electricity when solid?

No delocalised electrons/ no free moving electrons

When can ionic substances conduct electricity?

When they are liquid or molten

what is the conservation of mass

atoms cant be destroyed or created

when a metal forms a metal oxide, why does the mass increase

a gas is added

when an acid reacts with a metal, why does the mass decrease

gases produced and escaped

what is a mole

mass of a substance that contains 6.02 × 10²³ particles

which formula is used to calculate the number of mole from mass and Mr

moles = mass/Mr

what is a limiting reactant

when the reactant runs out before the product

what is the unit for concentration

mol

how is the modern periodic table ordered

by proton/ electron number(atomic mass)

how are the early list of elements ordered

by weight

why do elements in a group have similar chemical properties

they have the same number of electrons in the outer shell

what is the name given to group 1 elements

alkalines

what is the name given to group 7 elements

halogens

give the formula for the first 4 halogens

F2, Cl2, Br2, I2

what is the formula used to calculate the number of moles from mass and Mr

moles = mass/Mr

which formula is used to calculate the mass of a substance from number of moles and Mr

mass = moles * Mr

how can you convert a volume reading from cm³ to dm³

/1000

if the amount of solute in a solution is increased, what happens to its concentration?

increase

if the volume of water in a solution is increased, what happens to the concentration

decrease

which formula is used to calculate concentration from mass and volume

concentration = mass/volume

what is the unit for concentration

mol/dm³ or g/dm³

how many particles are in one mole of a substance

6.02 × 10²³ (avogadros constant)

what is one mole equivalent to

1 g

what is the formula to calculate moles

moles = mass/Mr