What is the approximate mass of an atom that contains 26 protons, 26 electrons and 19 neutrons?

What is the approximate mass of an atom that contains 26 protons, 26 electrons and 19 neutrons?

(1) 26 u

(2) 45 u

(3) 52 u

(4) 71 u

The mass of an atom is equal to the protons plus neutrons. Protons and neutrons are particles located inside the nucleus of an atom and give an atom most of it's mass. Therefore, all we need to do is simply add 26+19 to get 45 as the correct answer, making choice 2 correct.

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