Atomic structure

4. State where electrons “jump” to a higher energy level
5. Elements with the same number of protons and different number of neutrons are ____
13. State where electrons fill the lowest energy levels
14. Orbitals can hold a maximum of ___ electrons
15. Atoms are _____ when they are in an excited state
16. The sum of the protons and neutrons determines the ____ number
19. Region around the nucleus where electrons are most likely to be found
20. Subatomic particle with no charge
21. Negatively charged particle that orbits the nucleus

1. The ____ of an atom is hard and dense
2. _____ electrons are located in the outermost energy level
3. An atom is made up of mostly ____ space
6. The number of ____ determines the element
7. When electrons in an excited state return to lower energy levels, they emit energy in the form of _____
8. Electrons further from the nucleus contain ___ energy
9. Electrons want to be ____ as long as possible
10. Fundamental building block of matter
11. Charge of a nucleus
12. An atom is ___ if the number of protons equals the number of electrons
17. Electrons ______ energy when they move to a higher energy level
18. _____ number is determined by the amount of protons in an atom