What did John Dalton’s atomic theory say?
- All matter is made up of tiny particles called atoms
- Atoms are tiny, hard spheres that cannot be broken down into smaller parts
- Atoms cannot be created or destroyed
- The atoms in an element are all identical (but each element has its own type of atom)
What are the subatomic particles, their relative charge and relative mass?
Protons: +1, 1
Neutrons: 0, 1
Electrons: -1, 1/1835 (negligible)
What was Ernest Rutherford’s experiment and what did it suggest?
Tiny positive particles were fired at a thin gold foil. Most particles passed straight through with a few being deflected and a very small number bouncing back, suggesting that atoms are mostly empty space with a small positive central nucleus that contains most of the mass.
What is the mass number?
The total number of protons and neutrons in an atom.
What is the atomic number?
The number of protons in an atom.
What are isotopes?
Atoms of an element with the same atomic number but different mass number.
What is the relative atomic mass (RAM)?
The mean mass of an atom of an element relative to 1/12th the mass of carbon-12 isotope.
