Unit 1 Vocab Check

3. Atomic number 1, the most common element in the universe
8. This subatomic particle has a negligible mass
9. The number of protons and neutrons determine this for an atom
14. The other gas that stars are mostly made of
16. The first law of planetary motion implies that this is not constant
17. The measurement of how much mass is stored within a specific volume of a substance
20. The largest planet in the solar system
21. According to the second law of planetary motion, this is not constant
22. The star at the center of our solar system
23. The process that allows a star to create energy (2 words, no spaces)

1. Planetoids that solidify too quickly for metal to sink to the core are called this
2. The number of protons and electrons determine this for an atom
4. The name of the scientist who discovered the laws of planetary motion (last name only)
5. The average distance between the Earth and the Sun (2 words, no spaces)
6. The mysterious force that holds the nucleus of an atom together (3 words, no spaces)
7. The closest planet to the Sun (also, it's shrinking)
10. The name of the Greek scientist who discovered the water displacement form of measuring volume
11. The big scientific name for when a star isn't growing or shrinking (2 words, no spaces)
12. The identity of the mystery metal cylinder for our recent lab
13. Knowing the density of an unknown material let's us find this for the material
15. This substance originally wasn't on Earth due to its density being too low
18. This subatomic particle gives the identity of an atom
19. The cloud of gas and dust where stars are born
24. Planets orbit in this shape
25. This subatomic particle has no charge