Hey there! The answer you're looking for is Helium
Here shows the list of per shell
Hydrogen
Lithium
Beryllium
That really depends on the age of the periodic table you’re referring to. Mendeleev’s original periodic table had only 50 elements. Today, the most modern Periodic table has 118 elements.
50g U ( 1mol/ 238.03g) = .2 moles
238.03 is the molar mass of uranium- can be found on periodic table
Can you provide a some sort of picture of the atom or something, please?