Question

How many protons, electrons, and neutrons does an atom with atomic number 50 and mass number 125 contain?
a.
50 protons, 50 electrons, 75 neutrons
c.
120 neutrons, 50 protons, 75 electrons
b.
75 electrons, 50 protons, 50 neutrons
d.
70 neutrons, 75 protons, 50 electrons

Answer 1

The atomic number is the same as the number of protons in an atom

Each atom has the same number of electrons as it has protons

The mass number is the sum of the number of protons and neutrons.

A neutron weighs the same as a proton. An electron's mass is negligible.

Given all those things above - you have ALL you need to work out the answer...

Answer 2

The answer then is A right?

Answer 3

Yes

Answer 4

Thanks :)