3d - Solid Compounds

1. The elements scandium to zinc (Z = 21 to 30) are termed as the 3d block of elements or 3d-block of metals since here the first of the feasible d sub-shells is increasingly filled (3d-block - first row of the d-blocks).
2. The transition elements are group of industrially significant metals generally because of their strong inter-atomic metallic bonding giving them usually high melting/boiling points and high tensile strength.
3. These-called 'transition metal characteristics' occur from an unfinished d sub-shell energy level but scandium and zinc are not true transition metals that is Ti to Cu are the real transition elements (reasoning later).
4. Note:physically, zinc is low melting and a lower tensile strength compared to the anothers in the 3d block.
5. even though scandium is physically typical of a transition metal example high melting point and high tensile strength, chemically, scandium only creates a single and colourless triple charged ion (Sc³⁺). Therefore like zinc (only Zn²⁺), depicts non of the typical characteristics of transition metal chemistry example variable coloured complex ions, oxidation state, catalytic properties of the metal or ion. This is all described in detail later.
6. So possibly the best definition of a transition metal is an element which forms at least one ion with an not complete d sub-shell containing at least one electron. How this related to variable oxidation state and coloured complex ions is described further and the subsequent sections on the individual metals (links below) and some of the. Zinc (Zn²⁺, [Ar]3d¹⁰) and scandium (Sc³⁺, [Ar]3d⁰) cannot meet this criteria.
7. The existence of the partially-filled d sub-shells of electrons provides transition elements properties that are not in general possessed through the main group elements, namely Groups 1-7 and 0, BUT, there are similarities with other metals, mainly in Groups 2, 3 and 4.