Answer:
The atomic mass is 101.
Step-by-step explanation:
Protons and neutrons are the only particles that contribute to mass. Electrons do have a mass, but it's so miniscule and insignificant that it doesn't contribute to the mass of an atom. In every instance of calculating atomic mass, add the number of protons to the number of neutrons.
Therefore,
44 + 57 = 101
number of protons + number of neutrons = atomic mass
Also, there can never be a negative amount of protons or neutrons, so if you get a negative number, there's something wrong.
Bonus Information:
Don't confuse mass with charge! As it says in its name, neutrons are neutral or have no charge. Protons (+) and electrons (-) are the only particles that have a charge, so calculating that would be different.
If you were calculating the atomic charge with the same numbers, your answer would be:
44 - 42 = 2
Charge = +2
What To Remember:
M = p + n
C = p - e
C = atomic charge, M = atomic mass, p =protons, n = neutrons, e = electrons
I hope this helps!