$(a)$ Predict which of the following will form anions and which will form cations:
$(i)$ $Na$ $(ii)$ $Al$ $(iii)$ $Cl$ $(iv)$ $O$
$(b)$ Name two elements that are inert.

(A-D) $Cl$ and $O$ are non-metals with high electronegativity and will gain electrons to form anions ($Cl^-$ and $O^{2-}$).
$Na$ and $Al$ are metals with low ionization energy and will lose electrons to form cations ($Na^+$ and $Al^{3+}$).
$(b)$ Inert elements are those that have a stable valence shell configuration (octet or duplet) and do not react under normal conditions. Examples include $He$ (Helium) and $Ne$ (Neon).