The atomic number is 9 Ions have the same atomic number since atomic number signifies number of protons not electrons
This set up of a conversion table should show you that if you multiply
the grams of BeI2 times .02 moles, it equals <span>5.256 g (your answer) </span>
N=
l=
m(l)=
m(s)=
start with H^+ (no electrons) , then adding 5 electrons will be 1s2 2s2 2p1
so for the 5th electron
n = 2
l = 1
ml = -1
ms = 1/2