Most atoms follow the octet rule meaning they need electrons to fill their valence shells. One important exception is H which only needs electrons to fill its valence shell. full they blank

The octet rule means that atoms need a total of 8 valence electrons to fill their valence shell. Hydrogen only needs two to fill its valence shell.

Explanation:

All atoms except for hydrogen can hold a total of 8 valence electrons in their outer energy levels (2 in the s level, 6 in the p level). Hydrogen only has two electrons total, so it does not require more than the s level and two electrons to have a full valence.

hey there!

mass = 6.75 g

volume =   9 cm³

therefore:

d = mass / volume

d   = 6.75 / 9

d = 0.7 g/cm³

answer b