Across
1
Substance with pH below 7
4
Reddish electrical conductor
6
Basic unit of life
7
Hottest planet in solar system
10
Second lightest element
11
Form of thermal energy
12
Chemical element in table salt
13
Molten rock beneath Earth surface
Down
2
Gas form of a liquid
3
Naturally occurring inorganic solid
5
Nerve cell in the brain
6
Icy body with a tail near the sun
8
Fourth state of matter
9
Substance with pH above 7