Each element in the periodic table has: A unique symbol – a one or two-letter abbreviation used to represent the element. An ...

The full chemical symbol for an element shows its nucleon number (A) at the top, and its proton number (Z) at the bottom. This symbol tells you that the chlorine atom has 17 protons. It will also ...

The atomic number is shown below the chemical symbol, and the mass number is shown above. In this example the atomic number is 17 and the mass number is 35. This means that each of these atoms has: ...