Question

Number of electron in outermost orbital of alkali metal are

Answer 1

Alkali metals are the first group elements.
Therefore they have a new shell added and only one electron is present in that shell.

Now as the new shell is outermost, It becomes the Valence shell and the one electron present in it becomes valence electron.
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Answer 2

Answer:

There is only one electron in the outermost shell of alkali metals.

Hence,

The number of electrons in the outermost shell of alkali metals is 1.