Periodic Table

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Across
  1. 2. The smallest particle of an element that retains all the chemical and physical properties of the element.
  2. 3. Rows of the periodic table of elements. These represent successive principal energy levels for the valence electrons in the atoms of the elements involved.
  3. 4. The number of protons in the nucleus of an atom. Since this number is different for each element, elements are listed on the periodic table of elements in order of atomic number.
  4. 6. ATOMIC MASS A figure used by chemists to specify the mass—in atomic mass units—of the average atom in a large sample.
  5. 7. Another term for chemical symbols.
  6. 8. The center of an atom, a region where protons and neutrons are located. The nucleus accounts for the vast majority of the average atomic mass.
  7. 10. A positively charged particle in an atom. The number of protons in the nucleus of an atom is the atomic number of an element.
Down
  1. 1. Electrons that occupy the highest energy levels in anatom. These are the electrons involved in chemical bonding.
  2. 5. A substance made up of only one kind of atom, which cannot be chemically broken into other substances.
  3. 9. An atom or atoms that has lost or gained one or more electrons, thus acquiring a net electric charge.