How many neutrons are in an atom of #"_86^222Rn#?

1 Answer
Mar 5, 2017

Answer:

#136#

Explanation:

The #""_86^222Rn# atom has a mass number (at the top) of #222# and an atomic number (at the bottom) of #86#.

The mass number is the number of protons and the number of neutrons, each with mass of #1#, added together. The atomic number is just the number of protons.

Therefore, we can find out the number of neutrons by simply subtracting the two:

#222 - 86 = 136# neutrons.