Topic 1: Atomic Structure and the periodic table
- An atom has an equal number of protons and electrons.
- An isotope has the same number of protons, but have a different number of neutrons.
- Protons have a positive charge (+1) and a mass of 1.
- Electrons have a negative charge (-1) and a mass of 0.
- Neutrons have a neutral charge of 0 and a mass of 1.
- The number of protons and electrons cancel themselves out to give an atom a neutral charge overall.
- The elements in the periodic table are arranged in order of increasing atomic numbers.