91Ó°ÊÓ

The elements in Group$1\mathrm{A}\left(1\right)$ are metal while the elements in Grouprole="math" localid="1656591865204" $7\mathrm{A}\left(17\right)$ are non-metals. Grouprole="math" localid="1656591826381" $1\mathrm{A}\left(1\right)$ elements are lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr). These are also called alkali metals. Group$7\mathrm{A}\left(17\right)$ elements are fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). These are commonly known as halogens.

The elements in Group $\mathbf{1}\mathbf{A}\mathbf{\left(}\mathbf{1}\mathbf{\right)}\mathbf{}$ always form monoatomic cationsby losing their single valence electron, resulting in the generation of a single positive charge on them (for example${\mathbf{Li}}^{\mathbf{+}}$,) while the elements of Group $\mathbf{}\mathbf{7}\mathbf{A}\mathbf{\left(}\mathbf{17}\mathbf{\right)}\mathbf{}$ form monoatomic anions by gaining a single valence electron from their counterparts, resulting in the generation of a single negative charge on them (for example, $\mathbf{F}$).