Atoms, Elements, Compounds and Mixtures

What is an Atom?

All substances are made up of atoms. An atom is the smallest part of an element.

"Matter cannot be created or destroyed, only transformed."
— Law of Conservation of Matter
  • Atoms are represented by unique chemical symbols.
  • There are 118 elements in the Periodic Table.
Electronic Shell Electron Nucleus Proton & Neutron
Beryllium (Be) Atomic Structure

Elements, Compounds & Mixtures

Match the terminology to the correct definition by clicking them.

Element
Compound
Mixture
Two or more atoms that are chemically bonded.
A combination of substances that can be physically separated.
Consists of the same type of atoms.

Naming Compounds

Rule 1: -ide

Metal + Non-metal compound.
Example: Sodium + Chlorine = Sodium Chloride

Rule 2: -ate

3+ elements (one being Oxygen).
Example: Sodium + Carbon + Oxygen = Sodium Carbonate

Progress Check: Naming

Calcium + Bromine
Potassium + Iodine
Iron + Sulphur
Sodium + Iron Sulphate

Balancing Equations

How to Balance:

Balancing equations obeys the Law of Conservation of Matter: the total number of atoms of each element must be the same on both sides.

  1. Note the atoms of each element on the reactant (left) and product (right) side.
  2. Find multiples so they are equal. Change coefficients (the number in front), not subscripts.
H2 + O2 H2O
Balanced
Unbalanced
CO + O2 CO2
Balanced
Unbalanced
Al + Cl2 AlCl3
Balanced
Unbalanced
Fe + Br2 Fe2Br3
Balanced
Unbalanced
N2 + H2 NH3
Balanced
Unbalanced
Fe2O3 + CO → Fe + CO2
Balanced
Unbalanced
CH4 + O2 CO2 + H2O
Balanced
Unbalanced