Question

The atomic number of Uranium is 92. How many electrons are there in the neutral atom? How many electrons and protons are there in the $U^{+2}$ ion?

Answer 1

Atomic no. is the no of p+ in an atom. For any neutral species, no. of p+ = no. of e-

So Uranium has 92 e-...... U2+ means that 2 e- has been taken out of the atom so it now has (92 -2) e- that gives you 90 e-.

[P+ means proton , e- means electrons]

Hope this helps

Answer 2

"Atomic number of Uranium = 92

Number of protons = Number of electrons

Therefore, number of protons = 92

Number of neutrons = 143

Mass number = 92 + 143 = 253

The given ion of uranium = ${ U }^{ +2 }$

+2 charge indicates that two electrons are deduct from the atomic number

Therefore, electrons in ${ U }^{ +2 }$ = 92 - 2 = 90

Number of protons = Number of electrons.

Therefore, "number of protons" = 90"