Chemistry Unit 2

6. electrons occupy the lowest energy first
10. number of protons in the nucleus of an atom
12. are characterized by the presence of electrons in d orbitals
13. atoms that have the same number of protons but a different number of neutrons
14. contians protons and neutrons

1. number of wave cycles that pass a given point per unit of time
2. the time required for one half of the nuclei in a radioisotope sample to decay
3. a region of space in which there is a high probability of finding and electron
4. atoms can be broken into smaller, more fundamental particles, called
5. what takes up 80% of the periodic table
6. an ion with a negative charge
7. particles and rays emitted from the radioactive source
8. who arranged the periodic table in order of increasing atomic number
9. who used the scientific method or revise democritus's model
11. the total number of protons and neutrons in the nucleus of an atom