15:00 mins. The oxidation state, sometimes referred to as oxidation number, describes the degree of oxidation (loss of electrons) of an atom in a chemical compound.Conceptually, the oxidation state, which may be positive, negative or zero, is the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% ionic, with no covalent component. The elements with incompletely filled d-subshell in their ground state or most stable oxidation state are named as D-block elements.They are additionally named as transition elements.The partially filled subshells incorporate the (n-1) d subshell.All the d-block elements have a similar number of electrons in the furthest shell. This property is due to the reasons explained below: 1) These elements have numerous (n–1) d and ns electrons. •Low oxidation states are found when a complex compound has ligands capable of π-acceptor character in addition to the σ-bonding. Introduction to General Properties of the Transition Elements. Variable oxidation states: All transition elements display variety of oxidation states or variable valencies within their compounds. Delhi 2014) Answer: The variability of oxidation state of transition elements is due to incompletely filled d-orbitals and presence of unpaired electrons, i.e. Transition elements show variable state oxidation in their compounds. Periodic Trend and Chemical Properties of D- Block Elements (Part-2) 15:00 mins. (Comptt. Why do transition elements show variable oxidation states? Variable Oxidation state in Transition Elements. The stability of oxidation state depends mainly on electronic configuration and also on the nature of other combining atom. The elements which show largest number of oxidation states occur in or near the middle of series (i.e., 4s 2 3d 3 to 4s 2 3d 7 configuration). Except scandium, the most common oxidation state shown by the elements of first transition series is +2. However, other elements of the group exhibit +3 oxidation states such as Fe 2 O 3 and +4 oxidation state such as V 2 O 4. 5. i) These elements have several (n – 1) d and ns electrons. Reason of variable oxidation state is that there is a very small energy difference in between (n-1)d and ns orbitals. The variable oxidation states shown by the transition elements are due to the participation of outer ns and inner (n–1)d-electrons in bonding. 3. The transition elements in lower oxidation states (+2 and +3) generally form ionic bonds and in higher oxidation state … In p-block elements we have seen lower oxidation states are favoured by the heavier members (due to inert pair effect) whereas, we acknowledge an opposite trend in d-block. As a result ,electrons of (n-1)d orbitals as well as ns-orbitals take part in bond formation. • Transition elements have variable oxidation states ,due to very small energy difference between (n-1)d & ns sub-shell electrons from both the sub-shell take part in bonding Oxidation States 15. Why the Fe has the highest +6 oxidation state inspite of +8 ? (ns) and (n -1) d electrons have … This lesson will discuss the variable oxidation states possess by Transition Elements and some key points related to oxidation states. This oxidation state arises from the loss of two 4s electrons. The elements at the end of the series exhibit fewer oxidation states, because they have too many d electrons and hence fewer vacant d-orbitals can be involved in bonding. Answer: It is due to similar energy of (n – 1 )d and ns orbitals, electrons from both can be lost. This property is due to the following reasons. 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