Atomic Structure and the periodic table

• Nuclear reactions involve changes in the nucleus of an atom.
• Isotopes are atoms with different numbers of neutrons but the same number of electrons, so they have the same chemical properties.
• The atomic number is equal to the number of protons.
• Radioactive decay is when unstable atoms spontaneously change into more stable ones, releasing energy as they do so.
• Ions are charged particles formed when one or more electrons are lost from an atom (positive ion) or gained by an atom (negative ion).
• Atoms can be represented using symbols that show their relative proportions of protons, neutrons, and electrons.
• Atoms can be represented by symbols that show their elemental identity.
• Beta particles are electrons.