Across
1
Particle of light
4
Reddish electrical conductor
7
Compound containing oxygen
8
Second lightest element
12
Fourth state of matter
Down
2
Mass per unit volume
3
Blocking of light by a celestial body
5
Hottest planet in solar system
6
Magnetic metallic element
9
Smallest unit of an element
10
Gas essential for breathing
11
Amplified beam of light
13
Substance with pH below 7