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本课程“无机化学——d块与f块元素”将深入探讨元素周期表中d块（第3-12族）和f块（镧系和锕系）的元素。 **d块元素**： * 重点介绍d块元素的**金属特性**，如高强度、延展性、导电导热性以及高熔沸点，这些特性源于(n-1)d电子的参与形成的强原子间结合。 * 解释d块元素为何具有**可变价态**，以及由此产生的**顺磁性**、**催化性质**、**显色能力**、**形成配位化合物**和**间隙化合物**的倾向。 * 讨论d块元素的**化学性质**，包括与非金属的反应，以及金属氧化物的性质，并以**重铬酸钾**和**高锰酸钾**的制备与氧化性为例。 **f块元素**： * 介绍**镧系元素**，强调“**镧系收缩**”现象及其对后续元素化学性质的影响。 * 阐述镧系元素的**主要氧化态（+3）**以及其他可能出现的氧化态。 * 探讨**锕系元素**的**复杂化学性质**，特别是它们易出现的**多变氧化态**以及**放射性**带来的研究挑战。 **应用**： * 课程最后将提及d块和f块元素及其化合物的**广泛应用**，包括在合金、催化剂、有机合成等领域的重要性。
SUMMARYThe d-block consisting of Groups 3-12 occupies the large middle section of the periodic table. In these elements the inner d orbitals are progressively filled. The f-block is placed outside at the bottom of the periodic table and in the elements of this block, 4f and 5f orbitals are progressively filled.Corresponding to the filling of 3d, 4d and 5d orbitals, three series of transition elements are well recognised. All the transition elements exhibit typical metallic properties such as -high tensile strength, ductility, malleability, thermal and electrical conductivity and metallic character. Their melting and boiling points are high which are attributed to the involvement of (n -1) d electrons resulting into strong interatomic bonding. In many of these properties, the maxima occur at about the middle of each series which indicates that one unpaired electron per d orbital is particularly a favourable configuration for strong interatomic interaction.Successive ionisation enthalpies do not increase as steeply as in the main group elements with increasing atomic number. Hence, the loss of variable number of electrons from (n -1)d orbitals is not energetically unfavourable. The involvement of (n-1) d electrons in the behaviour of transition elements impart certain distinct characteristics to these elements. Thus, in addition to variable oxidation states, they exhibit paramagnetic behaviour, catalytic properties and tendency for the formation of coloured ions, interstitial compounds and complexes.The transition elements vary widely in their chemical behaviour. Many of them are sufficiently electropositive to dissolve in mineral acids, although a few are ‘noble'. Of the first series, with the exception of copper, all the metals are relatively reactive.The transition metals react with a number of non-metals like oxygen, nitrogen, sulphur and halogens to form binary compounds. The first series transition metal oxides are generally formed from the reaction of metals with oxygen at high temperatures. These oxides dissolve in acids and bases to form oxometallic salts. Potassium dichromate and potassium permanganate are common examples. Potassium dichromate is prepared from the chromite ore by fusion with alkali in presence of air and acidifying the extract. Pyrolusite ore (MnO2 ) is used for the preparation of potassium permanganate. Both the dichromate and the permanganate ions are strong oxidising agents.The two series of inner transition elements, lanthanoids and actinoids constitute the f-block of the periodic table. With the successive filling of the inner orbitals, 4f, there is a gradual decrease in the atomic and ionic sizes of these metals along the series (lanthanoid contraction). This has far reaching consequences in the chemistry of the elements succeeding them. Lanthanum and all the lanthanoids are rather soft white metals. They react easily with water to give solutions giving +3 ions. The principal oxidation state is +3, although +4 and +2 oxidation states are also exhibited by some occasionally. The chemistry of the actinoids is more complex in view of their ability to exist in different oxidation states. Furthermore, many of the actinoid elements are radioactive which make the study of these elements rather difficult.There are many useful applications of the d- and f-block elements and their compounds, notable among them being in varieties of steels, catalysts, complexes, organic syntheses, etc.
