Periodic Trends

Atomic Radius Half of the distance between two bonding atoms nuclei

Atomic Radius Trend Increases

Ionic Radius Compare ions to their neutral counterparts Ion: charged atom that results from the gaining or losing of electrons Cation: loses electrons and produces a positive charge Anion: gains electrons and produces a negative charge

Cations and Anions Of Representative Elements

Cation vs Atom

Anion vs Atom

Cation is always smaller than atom from which it is formed. Anion is always larger than atom from which it is formed.

9 Na + : [Ne]Al 3+ : [Ne] F - : 1s 2 2s 2 2p 6 or [Ne] O 2- : 1s 2 2s 2 2p 6 or [Ne]N 3- : 1s 2 2s 2 2p 6 or [Ne] Na +, Al 3+, F -, O 2-, and N 3- are all isoelectronic with Ne have the same number of electrons, and hence the same ground-state electron configuration Isoelectronic

Minimum energy required to remove an electron from a gaseous atom in its ground state Indication of how strongly an atom’s nucleus holds onto its valence electron Ionization Energy

12 General Trends in First Ionization Energies Increasing First Ionization Energy

Indicates an element’s ability to attract electrons in a shared chemical bond Electronegativity