Respuesta :

Answer: 45

Explanation:

Recall that mass number = number of protons + number of neutrons. Hence, the mass number of the atom

= 22 + 23

= 45

Furthermore, the atomic number is equal to the number of protons. Hence, since the number of protons is 22. the atom has an atomic number of 22

Thus, An atom that contains 22 protons,

23 neutrons, and 22 electrons would have a mass of approximately 45

Answer:

the atom  mass number is 45 because 22+23 = 45

Explanation: