Question #021e1

1 Answer
Stefan V.
May 15, 2017

#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.

http://symbolsnet.com/symbols/zinc-periodic-symbol.html

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)))#

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