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प्रश्न
Explain the trend in an Oxidation state of 3d elements.
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उत्तर
Trends in oxidation state of 3d elements:
- One of the notable features of transition elements is the great variety of oxidation states they show in their compounds.
- Loss of 4s and 3d electrons progressively leads to formation of ions. The transition elements display a variety of oxidation states in their compounds. Loss of one 4s electron leads to the formation of M+ ion, loss of two 4s electrons gives a M2+ ion while loss of unpaired 3d and 4s electrons gives M3+, M4+ ions and so on.
- As the number of unpaired electrons in 3d orbitals increases, the number of oxidation states shown by the element also increases. Scandium has only one unpaired electron. It shows two oxidation states while manganese with 5 unpaired d electrons shows six different oxidation states.
- The elements which give the greatest number of oxidation states occur in or near the middle of the series. Manganese, for example, shows oxidation states from +2 to +7.
संबंधित प्रश्न
Give the electronic configuration of europium (Z = 63).
Which of the following statements are FALSE about lanthanoids?
(I) They have lower heat of atomization than transition metals
(II) They are soft metals with silvery white colour and densities of about 7 g cm−3.
(III) They react with water to give the metal hydroxide and oxygen gas.
(IV) They form hydroxides, which are covalent and basic.
The electronic configuration of transition element 'X' in +3 oxidation state is [Ar] 3d4. What is its atomic number?
The only radioactive element among the lanthanoids is ____________.
When lanthanoids (Ln) are heated to about 2800 K with carbon, the carbides with general formula ____________ are obtained.
What is the general molecular formula of the product obtained on reacting lanthanoids (Ln) with nitrogen?
Which is the INCORRECT property of lanthanoids?
Which element among the following lanthanoids has the smallest atomic radius?
The observed electronic configuration of promethium (atomic number 61) is ____________.
Which element from following forms colourless compounds in +2 oxidation state?
Identify the correct decreasing order of ionic radii of lanthanoids.
Which of the following properties is NOT of lanthanoids?
Which among the following lanthanoids has smallest atomic size?
Give the properties of Lanthanoids.
Lanthanoids and actinoids resemble in ______.
Which of the following factors may be regarded as the main cause of lanthanoid contraction?
The most basic hydroxide from the following is:
Identify the last element in lanthanoid series.
Which element from following has largest atomic radius?
Give the electronic configuration of gadolinium (Z = 64).
Write expected and observed electron configurations of 58Ce.
Eu (Z = 63) and Yb (Z = 70) show + 2 oxidation state. Explain.
What are the physical properties of lanthanoids?
Write two uses of lanthanoids.
