When a gas is compressed in a cylinder the amount (mass) of gas
a.

increases
b.

decreases
c.

increases initially then decreases
d.

remains unchanged

n has four pairs of electrons in the valence shell, electrons repel one another ,n has 7 protons in its nucleus, and since n has 7 protons, it must fill the second shell, giving it 4 pairs of electrons. the electrons form 3 bonds and 1 lone pair of electrons. each pair of electrons repels the other pairs, so they are equally far apart.

so all of the above