1.3 Atom & Periodic table

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Across
  1. 2. mass, the total mass of particles of matter in an atom.
  2. 6. cloud, a group of electrons circulating around a nucleus or a molecule.
  3. 7. Property, a characteristic of a substance that can be observed using our senses.
  4. 8. an atom group of atoms that has an electron charge.
Down
  1. 1. a substance whose atoms all have the same atomic number.
  2. 3. Symbol, a one or two letter notation that is used for denoting the chemical elements.
  3. 4. number, the total number of protons in the nucleus of an atom.
  4. 5. Table, a horizontal row of a periodic table.