Across
1
Second lightest element
5
Absolute temperature scale unit
6
Element found in all living things
7
Chemical element in table salt
9
Unit of force
10
Measure of matter in an object
12
Force that attracts objects together
Down
2
Group of similar cells
3
Curved glass that refracts light
4
Molten rock beneath Earth surface
8
Gas essential for breathing
11
Positive particle in nucleus
13
Biological catalyst
14
Solid with repeating atomic pattern