1.8-1.33 Elements Compounds, Mixtures, Atomic Structure, The Periodic Table, Chemical formulae, equations, and calculations

Elements

• can’t be split into anything simpler

• All same number of protons

Element example

• copper

• iron

• magnesium

Compounds

• substance made of 2 or more elements which are chemically combined

• unlimited number of compounds

• Can’t be separated into their elements as they’re chemically bonded

Mixtures

• combination of 2 or more substances (element or compound)

• can be separated

Mixture example

• oil and water

• sand and water

Simple distillation DEFINITION

Separating components of a solution

Process of simple distillation

1) Start with a mixture of ethanol and water

2) Separate them using boiling points

Filtration DEFINITION

Separating the insoluble solid from the liquid

Process of filtration

1) Solid gets collected on filter paper

2) liquid passes through and is collected in a separate container

Paper chromatography DEFINITION

separating the solubles from a solution

Paper chromatography process

1. Start by drawing a baseline on the chromatography paper using a pencil

2. Place a small spot of the sample mixture on the baseline.

3. Pour the solvent into a beaker. ...

4. Allow the solvent to slowly travel upwards through the paper, taking with it a few soluble pigments from the sample mixture

Rf value

distance traveled by dye / distance traveled by solvent front

Fractional distillation

• crude oil gets vaporised

• columns are hot and cold from different boiling points so they condense

• hot gases rise to their boiling points

• crude oil vaporises

Fractional distillation in crude oil order

• Bitumen

• Fuel oil

• Diesel

• Kerosene

• Petrol

• Butane and propane

Crystallization definition

Separating the solute from the solution

Crystallisation process

Put solution in evaporating basin, and allow solvent to evaporate through boiling. The solvent will be left in the basin after all solvent evaporates

Rf value meaning

Used to identify unknown chemicals if they can be compared to a range of reference substances

• always the same if the same solvent and stationery phase are used

1) Name

2) Atomic number

3) Symbol

4) Atomic mass

Mass of proton

1

Mass of neutron

1

Mass of electron

0

Charge of proton

1

Charge of neutron

0

Electron

-1

Atomic number

number of protons in an atom

Mass number

number of protons and neutrons in an atom

Isotopes

Atoms with same number of protons but different number of neutrons

Ar (relative atomic mass)

Average mass of an atom compared to the 1/12th mass of carbon

Ar from isotopic abundances

(% of isotope 1 x mass of isotope 1) + (% of isotope 2 x mass of isotope 2)

(multiply the mass number of each isotope by percentage abundance —> add together and divide by 100)