Counting Subatomic Particles

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Across
  1. 2. The average mass of all the natural isotopes of an element, found on the periodic table.
  2. 4. Atoms of the same element with differing numbers of neutrons.
  3. 5. The sum of protons and neutrons in the nucleus of a single atom.
  4. 6. Subatomic particle that is in the nucleus and has no charge.
  5. 10. Subatomic particles that move quickly around the nucleus in discrete orbits and have a negative charge.
Down
  1. 1. Particles that make up the atom; includes protons, neutrons, and electrons.
  2. 3. The number of protons in an atom’s nucleus, found on the periodic table
  3. 7. The small, dense, central region of the atom where protons and neutrons are located.
  4. 8. Subatomic particle that is in the nucleus and has a positive charge.
  5. 9. Smallest form of matter that still retains the properties of the element.