Simple Machines

3. Where the electrons float around the nucleus.
4. Element with atomic number 8.
5. The property in which the periodic table is currently organized.
11. Number of electrons in the first shell of the electron cloud.
12. There are only 17 of these on the periodic table but are essential for life.
16. The process of an atom losing energy
17. The building block of matter.
19. Atoms with the same number of protons with differing numbers of neutrons.
20. There are 7 rows or ___________ on the modern periodic table.
21. After the first shell, each electron shell can hold this number of electrons.

1. The electrons are the ___________ particles found in the atom.
2. The two subatomic particles that make up the majority of an atom's mass.
6. Created the first periodic table.
7. a term used for nonmetals that are easily broken.
8. Original property that Mendeleev used to organize the elements.
9. Where the protons and neutrons are located in the atom.
10. The amount of time it takes for half of a sample of an element to decay.
13. Found in the nucleus with the protons.
14. a term used for metals that can be hammered or reshaped without breaking.
15. Positively charge subatomic particles
18. Adding protons and neutrons together gives you the atom's _______ number.
22. There are 18 columns or _________ on the modern periodic table.