# Do alkali metals not form diatomic molecules?

I know hydrogen forms a diatomic molecule $\ce{H2}$, where the electronic configuration of hydrogen is $\ce{1s}$.

But why doesn't lithium also form a diatomic molecule? Its electronic structure is $\ce{1s^2 2s}$, so can't two lithium atoms come together, share their outer electron and form $\ce{Li2}$? Same with $\ce{Na}$, $\ce{K}$ etc.

Am I missing something obvious?

• Note that this is one of the properties that is usually taught at elementary level to differentiate hydrogen from alkali metals, even though they occupy the same group. In fact, some periodic tables depict hydrogen with a "dual position" - in both group 1 and group 17, since it shares several properties of both alkali metals and halogens. I'll spare the details for a high school textbook and this quora page. – Gaurang Tandon Feb 24 '18 at 16:12
• Strongly related: chemistry.stackexchange.com/questions/32686/… – Nilay Ghosh Feb 24 '18 at 16:23