Across
1
Positive particle in nucleus
4
Unit of power
5
Gas essential for breathing
6
Blocking of light by a celestial body
7
Substance with pH below 7
Down
1
Particle of light
2
Magnetic metallic element
3
Mass per unit volume
8
Curved glass that refracts light
9
Element found in all living things
10
Hottest planet in solar system