Oxygen has an atomic number of 8 and an atomic mass of 16. How many valence electrons does it have?

2

4

6

8

16

Answer: 6 valence electrons

Explanation: the valence electron is the number of electron in the outermost shell of an atom.

Oxygen has an atomic number of 8. The electronic configuration will be 1s2 2s2 2p4 or 2, 6. Meaning the last shell is having 6 electrons and this is equivalent to the valence electron