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strictly, zinc, cadmium and mercury aren’t considered transition metals. IUPAC definition of a transition metal states that it must be ‘an element whose atom has an incomplete d sub-shell, or gives rise to cations with an incomplete d sub-shell‘. Zinc, cadmium and mercury all have the electronic configuration d10s2; although they commonly form +2 ions, these involve the loss of the s electrons. However, they can also exist in a +1 oxidation state.

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Oxidation Number: rule: the sum of all oxidation numbers on neutral compounds is 0; oxidation number indicates the number of electrons lost, gained or shared as a result of chemical bonding; the change in oxidation state of a species lets you know if it has undergone oxidation or reduction; the oxidation number of an atom in the elemental state is zero

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25.08ct Bi-Color Ametrine from Bolivia Nearly all ametrine comes from the Anahi mine in southeastern Bolivia. Amethyst and citrine are both quartz. It is rare for both colours of quartz to be found in the same crystal. Citrine and amethyst are colored by traces of iron, but the color of the zones visible within ametrine are due to differing oxidation states of iron within the crystal. The different oxidation states occur due to temperature differences across the crystal during its…

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