[tex]element \: with \: 2 \: atomic \: number \\ \\ is \: stable \: because \: it \: has \: already \: \\ \\ completed \: its \: orbit \: \\ \\ but \: atomic \: number \: with \: 3 \: and \: 9 \\ \\ will \: have \: to \: become \: stable \: \\ \\ after \: giving \: one \: electron \\ \\ so \: \: element \: with \: 3 \: and \: 9 \: atomic \: number \\ \\ is \: most \: reactive[/tex]
