What is the significance of the number 188 in Rhenium-188?

Question:

What does the number 188 mean in Rhenium-188?

Answer:

The number 188 in Rhenium-188 represents the total number of protons and neutrons in the atom, known as the atomic mass. In this isotope there are 75 protons and approximately 113 neutrons.

The number 188 in Rhenium-188 indicates the atomic mass of the isotope, which is derived from the total number of protons and neutrons in the nucleus of the atom. Rhenium-188 specifically has an atomic number of 75, which means it has 75 protons. By subtracting the number of protons from the atomic mass number, we find that there are approximately 113 neutrons in Rhenium-188. This unique combination of protons and neutrons distinguishes Rhenium-188 as an isotope of Rhenium.