Select the correct answer.
An element has atomic number 10 and an atomic mass of 20. How many neutrons are in the atom of this element?
A.10
b.20
D. 0
E. 200

answer: mercury

explanation:

answer:

the answer is 6 valence electrons.

explanation:

valence is the # of electrons on the outer most shell of an atom.

oxygen has 6.

although, the valency of oxygen is 2, because it only needs to make 2 covalent bonds, or gain 2 electrons, to achieve the stable octet configuration of a noble gas.

that's it!

if you need further assistance, let me know: )

~ trueboss72