How many electrons are lost from oxygen? co2 + h2 —> co + h2o a. 0 b. 1 c. 2 d. 3

a compound is a molecule made of atoms from different elements.

a. by the combination of an unlimited number of elements

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.