Atoms and periodic table

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  1. 5. abbreviations used in chemistry
  2. 7. a part or aspect of something abstract, especially one that is essential or characteristic.
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  1. 1. a characteristic of a substance that can be observed or measured without changing the identity of the substance.
  2. 2. a table of elements organized in their atom number
  3. 3. The mass number also called atomic mass number or nucleon number, is the total number of protons and neutrons
  4. 4. an atom or molecule with a net electric charge due to the loss or gain of one or more electrons.
  5. 6. The number of protons in a nucleus