Question

A particle P has 18 electrons, 20 neutrons and 19 protons. This particle must be:

• A. A molecule
• B. A binary compound
• C. An anion
• D. A cation

Answer 1

Potassium $K^{+}$

Because the particle P has 19 protons, this means that its atomic number is 19 and hence it is a potassium particle. It has 18 electrons means it has lost an electron, therefore it is a positive ion.