2. Atoms & Elements

What is the mass number of the most common isotope of potassium?

An element has two naturally occurring isotopes. One has an abundance of 37.40% and an isotopic mass of 184.953 amu, and the other has an abundance of 62.60% and a mass of 186.956 amu. What is the average atomic mass of the element?

What is the atomic number for potassium?

Which term is defined as the sum of protons and neutrons in an atom?

An atom has 20 electrons and 20 neutrons. What is the atomic mass of this atom if it also has 20 protons?