What is the maximum number of electrons allowed in the third energy level

18 electrons allowed in the 3rd energy level

The maximum number of electron in the first energy level (n = 1) is 2 (1)2 = 2 electrons. The maximum number of electron in the second energy level (n = 2) is 2 (2)2 = 8 electrons. The maximum number of electron in the third energy level (n = 3) is 2 (3)2 = 18 electrons etc ...

give me abc and i will get it for u.

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.