How many protons and neutrons are in an atom of Mo-94?
This is a great example of a question that actually provides you with the answer.
The quick answer here is that there are
As you know, the mass number,
This means that the mass number of a given isotope essentially tells you how many protons and neutrons are present in its nucleus.
In your case, molybdenum-94 has a mass number of
To find the specific number of protons and of neutrons, grab a periodic table and look for molybdenum,
Its atomic number,
This leaves you with
#"no. of neutrons" = A - Z#
#"no. of neutrons" = 94 - 42 = "52 neutrons"#