Across
1
Measure of matter in an object
4
Unit of energy
8
Nerve cell in the brain
Down
2
Second lightest element
3
Hottest planet in solar system
5
Smallest unit of an element
6
Ball of burning gas in space
7
Positive particle in nucleus
Measure of matter in an object
Unit of energy
Nerve cell in the brain
Second lightest element
Hottest planet in solar system
Smallest unit of an element
Ball of burning gas in space
Positive particle in nucleus