Across
1
Fourth state of matter
3
Reddish electrical conductor
7
Curved glass that refracts light
9
Element found in all living things
Down
2
Gas form of a liquid
4
Tectonic landmass section
5
Nerve cell in the brain
6
Second lightest element
8
Measure of matter in an object
10
Gas essential for breathing
11
Smallest unit of an element
12
Blocking of light by a celestial body