Across
1
Gas form of a liquid
4
Unit of force
6
Second lightest element
7
Mass per unit volume
8
Substance with pH above 7
9
Gas essential for breathing
10
Fourth state of matter
Down
2
Icy body with a tail near the sun
3
Force that attracts objects together
5
Center of an atom or cell
10
Tectonic landmass section
11
Glass that splits light into spectrum
12
Measure of matter in an object