ATOMS AND REACTIONS

2.1.1 + 2.1.2

Relative Atomic Mass (Ar)

The weighted average mass of an atom of an element relative to 1/12th the mass of an atom of carbon-12.

Moles

1 mole is the amount of substance which contains as many particles as there are atoms in exactly 12g of carbon-12

Empirical & Molecular

Empircal formula - The SIMPLEST whole number ratio of atoms of each element in a compound.

Molecular formula - The ACTUAL number of atoms of each element in a molecule.

Hydrated and anhydrous salts

Hydrated = have water of crystallisation

Anhydrous = no water

Calculation of the formula of a hydrated salt

The ideal gas equation

Percentage yield equation

Percentage yield example

Atom economy

Atom economy example

Oxidation rules

Group 1 = +1

Group 2 = +2

Group 3 = +3

Fluorine = -1

Hydrogen = +1 without metal, -1 with metal

Oxygen = mostly -2, peroxides/F -1/+2

Chlorine = mostly -1, positive with O or F

Orbital

An orbital is a region within an atom that can hold up to two electrons (with opposite spins)

Orbital shapes

Electron structure

Arrangement of electrons in sub shells

Electron config - 2s_¹

2 = period number

s = block element

1 = how far in that period