MCQ
Most of the radio active elements are present in:
- ALanthanoids
- BActinoids
- CRepresentative elements
- DSecond transition series
Explanation:
The actinoids are radioactive elements and the earlier members have relatively long half-lives.
The most common and known element is Uranium, which is used as nuclear fuel when its converted into plutonium, through a nuclear reaction.
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|
सूची-$I$ coordination compounds |
सूची-$II$ numbar of unpaired electrons |
| $A$ $\left[ Cr ( CN )_6\right]^{3-}$ | $I$ $0$ |
| $B$ $\left[ Fe \left( H _2 O \right)_6\right]^{2+}$ | $II$ $3$ |
| $C$ $\left[ Co \left( NH _3\right)_6\right]^{3+}$ | $III$ $2$ |
| $D$ $\left[ Ni \left( NH _3\right)_6\right]^{2+}$ | $IV$ $4$ |
Choose the correct answer from the options given below :-
Reason : Oxidation state of $Cl$ in $HClO_4$ is $+7$ and in $HClO_3$, it is $+ 5$.