Answer:
The answer to your question is: 3
Explanation:
If an atom has 5 electrons, 5 neutrons and 5 protons, it means that the element is Boron. Boron is situated in the third group A, that means that is has 3 elements in its outermost shell.
Also, if we do the electronic configuration:
1s² 2s²2p¹
If we count the number of electron in the second level of energy, the result will be: 2 in s and 1 in p = 3. Those are the valence electrons.
