Question

how many valence electrons are in a neutral atom of hydrogen?

Explanation:

Step1: Recall electron - configuration concept

The electron - configuration of hydrogen is $1s^1$.

Step2: Define valence electrons

Valence electrons are electrons in the outermost shell.

Step3: Determine number of valence electrons

Since hydrogen has only one electron in its only shell ($1s$), the number of valence electrons is 1.

Answer:

1