Consider oxygen, which has an atomic number of 8 and an atomic mass of 16. how many valence electrons does it have? a. 2

The maximum size of the inner shells are 2,8,18...
Valence electrons are found in the outermost shell of an atom (most of the time).
So the valence electrons of oxygen lies in the second shell, which has 8-2=6 valence electrons.

The independent variable is the type of music.the dependent variable is the pulse rate.the intervening variable is the age of the subject.if the mother does not like rock, her pulse is likely to not increase.the same might be true for the sister.the friend may like rap and gets excited.to establish cause/effect relationship, all of the subjects must be consistent.hope i .