Fission reactions can get out of control without neutron moderation. The correct option among all the options that are given in the question is the fourth option or option "D". The other options in this question can be discarded. I hope that this is the answer that you were looking for and it has come to your help.
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#7 Is TAXONOMY
Answer:
They have electrons in their 3d- and 4s-orbital for bond formation.
Explanation:
d- metals or transition metal are metal which form ion with partially filled d-orbital. Examples are iron and manganese.
The metals have 2 electrons in their 4s orbital. If only this is used for bonding, they will form compounds where they have oxidation State of +2 as seen in MnO.
If two 4s and one of 3d electrons are used, oxidation state of +3 is formed as seen in FeCl3.
If two 2s electron I used with two 3d electrons, compound with oxidation state of +4 is formed as seen in MnO2