Across
1
Positive particle in nucleus
4
Magnetic metallic element
5
Unit of energy
6
Smallest unit of an element
10
Gas essential for breathing
12
Substance with pH below 7
Down
2
Naturally occurring inorganic solid
3
Unit of heredity
7
Preserved remains of ancient life
8
Disturbance that transfers energy
9
Absolute temperature scale unit
11
Particle of light