Across
1
Hottest planet in solar system
3
Measure of matter in an object
6
Tectonic landmass section
7
Center of an atom or cell
8
Mass per unit volume
12
Smallest unit of an element
14
Precious yellow metallic element
Down
2
Solid with repeating atomic pattern
4
Chemical element in table salt
5
Unit of heredity
9
Blocking of light by a celestial body
10
Path of a planet around the sun
11
Our home planet
13
Basic unit of life
15
Element found in all living things