Question

How many protons and neutrons are in an atom of Mo-94?

Answer 1

`94` protons and neutrons.

Explanation:

This is a great example of a question that actually provides you with the answer.

The quick answer here is that there are `94` protons and neutrons in a molybdenum-94 isotope, `""^94"Mo"`.

That is the case because an element's isotopes are distinguished using their mass number, which is added to the name of the isotope using a hypen.

As you know, the mass number, `A`, tells you the number of nucleons present in the nucleus. A nucleon is simply a proton or a neutron.

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 `94`, which means that it contains `94` protons and neutrons in its nucleus.

To find the specific number of protons and of neutrons, grab a periodic table and look for molybdenum, `"Mo"`. You'll find the element listed in period 5, group 6.

Its atomic number, `Z`, which tells you how many protons are present in the nucleus, is equal to `42`. This means that the nucleus of any isotope of molybdenum will contain `42` protons.

This leaves you with

`"no. of neutrons" = A - Z`

`"no. of neutrons" = 94 - 42 = "52 neutrons"`