The ________ of an element is the total number of protons and neutrons in the ________ oh an atom.

Expert Answers
steveschoen eNotes educator| Certified Educator

Hi, nelson,

The mass number of an element is the total number of protons and neutrons in the nucleus of an atom.

I am assuming that there is a typo, "oh" --> "of"

Good luck, nelson.  I hope this helps.

Till Then,

Steve

ayl0124 | Student

The mass number of an element is the total number of protons and neutrons in the nucleus of an atom.

There is also a thing called the atomic mass, which is the average mass of all the isotopes of that element. While all atoms of an element must have the same number of protons, they can differ in the number of neutrons. Also, note that electrons are too small to affect the total mass of an atom.