Across
- 4. Percentage of each isotope of an element in nature.
- 7. Calculation used to determine atomic mass from isotopes.
- 8. Positively charged particle found in the nucleus.
- 12. Term for particles smaller than an atom.
- 13. Region of space where an electron is most likely to be found.
- 14. Ancient philosopher who first suggested the idea of atoms.
- 15. Number Sum of protons and neutrons in an atom.
Down
- 1. Negatively charged particle that orbits the nucleus.
- 2. Number of protons in the nucleus of an atom.
- 3. Scientist who developed a model of the atom with electrons in energy levels.
- 5. Neutral particle located in the nucleus.
- 6. The smallest unit of matter that retains the properties of an element.
- 9. Dense center of an atom containing protons and neutrons.
- 10. Weighted average mass of the isotopes of an element.
- 11. Atoms of the same element with different numbers of neutrons.