Question

an atom of gallium has 31 proton and a mass number of 70 what is the atomic number for an atom of gallium

Answer 1

Answer: The correct answer is 31.

Explanation:

Atomic number is defined as the number of protons or electrons that are present in a neutral atom.

Atomic number = number of protons = number of electrons

Mass number is defined as the sum of number of protons and neutrons that are present in an atom.

Mass number = Number of protons + Number of neutrons

We are given:

Number of protons = 31

Mass number = 70

Number of neutrons = Mass number - Number of protons = 70 - 31 = 39

Atomic number will be equal to the number of protons present in an atom which is 31

Hence, the correct answer is 31.

Answer 2

Hello!

Atomic Number, is the number where the atom lays on the perodic table and can be found through the number of protons. Meaning that gallium has an atomic number of 31 !

Atomic weight, which is equal to 70 in this case, can be found by subtracting the atomic number from that total to find the remaining number of neutrons that make up the mass. So gallium has 31 protons and 39 protons.

Hope this helps answer your question.