\(\mathrm{H}_{2}^{2+}(1+1-2=0)=\sigma 1 \mathrm{s}^{0}\)

Bond order \(=0\)

\(\mathrm{He}_{2}(2+2=4)=\sigma 1 \mathrm{s}^{2},{ }^{\star} \mathrm{fs}^{2}\)

Bond order \(=\frac{N_{0}-N_{a}}{2}=\frac{2-2}{2}=0\)

\(\mathrm{So}, \mathrm{both} \mathrm{H}_{2}^{2+}\) and \(\mathrm{He}_{2}\) do not exist.