What does the period number tell about the energy levels occupied by electrons in an atom?
A. The period number tells how many electrons are in the highest
energy level of the atom.
B. The period number tells which is the highest energy level occupied
by the electrons.
C. The period number tells how many electrons are in each sublevel
of the atom.
D. The period number tells how many energy sublevels are occupied
in the atom.

B. The period number tells which is the highest energy level occupied by the electrons

Explanation:

Thus, we can say that the period number tells which is the highest energy level occupied by the electrons in an atom.

hence, the correct option is B. The period number tells which is the highest energy level occupied  by the electrons.

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!

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