electrons and bonding

• Pi bond (π bond)

  A bond formed by the sideways overlap of two p orbitals, containing two electrons and with the electron density concentrated above and below the line joining the nuclei of the bonding atoms.
• Polyatomic ion

  An ion containing more than one atom.
• Sigma bond (σ bond)

  A bond formed by the overlap of one orbital from each bonding atom, consisting of two electrons and with the electron density centred around a line directly between the nuclei of the two atoms.
• Lone pair

  An outer shell pair of electrons that is not involved in chemical bonding
• Metallic bonding

  The electrostatic attraction between positive metal ions and delocalised electrons
• Anion

  A negatively charged ion with more electrons than protons
• Atomic orbital

  A region around the nucleus that can hold up to two electrons, with opposite spins
• Binary compound

  A compound containing two elements only
• Bonded pair

  A pair of electrons shared between two atoms to make a covalent bond
• Cation

  A positively charged ion with fewer electrons than protons
• Coordinate bond

  A shared pair of electrons in which the bonded pair has been provided by one of the bonding atoms only. Also called a dative covalent bond
• Covalent bonding

  The strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms
• Dative covalent bond

  A shared pair of electrons in which the bonded pair has been provided by one of the bonding atoms only: also called a coordinate bond
• Delocalised electrons

  Electrons that are shared between more than two atoms
• Electron configuration

  A shorthand method for showing how electrons occupy sub-shells in an atom
• Giant covalent lattice

  A three-dimensional structure of atoms, bonded together by strong covalent bonds
• Giant ionic lattice

  A three-dimensional structure of oppositely charged ions, bonded together by strong ionic bonds
• Giant metallic lattice

  A three-dimensional structure of positive ions and delocalised electrons, bonded together by strong metallic bonds