atoms/isotopes/ions

• Some isotopes are unstable and can decay into other elements. Decay involves emitting radiation such as alpha, beta, and gamma radiation.
• Isotopes are atoms with the same number of protons but different number of neutrons.
• 1. Electrons orbit the nucleus at specific energy levels which are also called shells.
• 2.The shells get progressively further from the nucleus and increase in energy level
• 3.Electrons can absorb electromagnetic radiation and jump to a higher energy level / shell. In these cases we say that the electron has become 'excited'.
• 4.Excited electrons can later fall back to a lower energy level, and emit electromagnetic radiation in the process. Electrons can also absorb enough energy to leave the atom altogether, this is known as ionisation.