MCQ
How many electrons can be fit into the orbitals that comprise the ${3^{rd}}$ quantum shell $n = 3$
- A$2$
- B$8$
- ✓$18$
- D$32$
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$Cr _2 O _7^{2-}+ XH ^{+}+6 Fe ^{2+} \rightarrow YCr ^{3+}+6 Fe ^{3+}+ ZH _2 O$
The sum of $X . Y$ and $Z$ is $.......$.