mass number (A); number of protons and neutrons in the nucleus
atomic number (Z); number of protons in the nucleus
- isotopes of an element; the same atom with different numbers of neutrons but same number of protons in the nucleus
- orbital; physical space that an electron can occupy within an energy level
- ionisation energy; amount of energy required to remove an electron from one mole of atoms in the gaseous state
- first ionisation energy; energy per mole needed to remove one/first most loosely bound electron from a neutral atom in the gaseous state.
- electronegativity; measure of an atom’s ability to attract an electron
- ionic bonding; an electrostatic attraction between oppositely charged ion
- covalent bonding; an electrostatic attraction between a pair of electrons and a positively charged nuclei
- polar; measure of attraction of an atom for electron pairs in its covalent bond
- resonance structure; any of two or more possible structures of the same compound.