Question

which is a outermost shell of hydrogen atom ?

Answer 1

1 is outermost she'll number

Answer 2

It has only one electron in its valence shell. The number of electrons that an atom must acquire, or lose, or share to reach a stable configuration of 8 (2 for hydrogen) is called its valence. Hydrogen, lithium, sodium, and potassium atoms all have a single electron in their outermost shell.
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