WAEC - Chemistry (2016 - No. 3)
How many electrons are present in \(^9_4Be^{2+}\)?
2
4
5
6
Erläuterung
Neutral Be has 4 electrons but \(Be^{2+}\) means it has lost two electrons from possible four and became a positive ion.
\(\therefore\) the number of electrons left will be equal to two.