Question

Question #021e1

Answer 1

`36` neutrons.

Explanation:

One way we have of differentiating between various nuclides of the same element is by writing the name of the element followed by a hyphen and the mass number of the nuclide.

In your case, you would have zinc-66, a nuclide of zinc that has a mass number equal to `66`.

Now, an atom's mass number, `A`, tells you the number of protons, which is given by the atomic number, `Z`, and neutrons present inside the atom's nucleus.

`color(blue)(ul(color(black)("mass number = no. of protons + no. of neutrons")))`

Alternatively, you can write

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

Grab a Periodic Table and look for zinc, `"Zn"`. You'll find it located in period 4, group 12. Look at its element box and make a note of its atomic number.

As you can see, zinc has

`Z = 30`

You already know from the nuclide's isotope notation that

`A = 66`

This means that you have

`color(darkgreen)(ul(color(black)("no. of neutrons" = 66 - 30 = 36)))`