Across
1
Icy body with a tail near the sun
4
Second lightest element
5
Gas essential for breathing
7
Gas form of a liquid
8
Unit of force
Down
2
Fourth state of matter
3
Smallest unit of an element
6
Particle of light
Icy body with a tail near the sun
Second lightest element
Gas essential for breathing
Gas form of a liquid
Unit of force
Fourth state of matter
Smallest unit of an element
Particle of light