How many oxygen atoms in 3.161*10^21 molecules of co2?

Explanation:

You need to know one piece of information for these problems. That is as follows:

There are 6.02 x 10^23 atoms in a mole of atoms or 6.02 x 10^23 molecules in a mole of molecules (actually there are 6.02 x 10^23 in a mole of anything).

So in 3.161 x 10^21 molecules of CO2 there are 3.161 molecules x (1 mole CO2/6.02 x 10^23 molecules CO2)= ?? moles CO2. Then multiply that by 2 to find the moles of O in CO2.

The others are done th same way.

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.