periodic table

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Across
  1. 2. number The sum of the numbers of protons and neutrons in the nucleus of an atom
  2. 3. Charged particles that has an UNEVEN number of protons and electrons
  3. 5. A substance that cannot be broken down into simpler substances by chemical means
  4. 7. symbol A one, two, or three letter abbreviation of the name of an element
  5. 8. table An arrangement of the elements in order of their atomic numbers such that elements with similar fall in the same group or column
Down
  1. 1. property Property of an element that you use your senses
  2. 4. number The number of protons in the nucleus
  3. 6. cloud A region round the nucleus of an atom where electrons are likely to be found