Atomic Theory

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