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TopNewestREALLY GREAT WIKI. I LIKED THAT.ALL THE BEST FOR FURTHER WIKIS – Vishwathiga Jayasankar · 2 years, 6 months ago

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– A K · 2 years, 6 months ago

Thanks :-)Log in to reply

You sure like Matrices and Determinants a lot , don't you mate ? – Azhaghu Roopesh M · 2 years, 6 months ago

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– A K · 2 years, 6 months ago

Yes, I am very interested in algebra.Log in to reply

Why iron has sometimes valancies 2 or 3? – Sonu Chauhan · 2 years, 6 months ago

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– A K · 2 years, 6 months ago

I don't know how this is related to my note,but I'll be happy to help you and I am very interested in chemistry by the way. The last two orbitals of iron are (4s and 3d) are very close in energy, so sometimes Iron gives up its 2 outer 4s electrons, and sometimes it also gives up an 3d electron m beside the two 4s electrons, because of that Iron ion having either Fe+2 or Fe+3 which are respectively named as ferrous and ferric.Log in to reply