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Important Topics for the class 12 chemistry From Chapter Solutions

From the solution chapter, below are some of the most relevant topics: Positive and negative deviation, Raoult’s rule, and colloidal characteristics

Topics from the d and f blocks of the chapter are highlighted: Transition metals can have different oxidation states. Transition metal ion formation of coloured ions, Lanthanoid contraction, and actinoids’ oxidation states are all covered in this chapter.

A block element is an element that makes up a building block.

The electronic configuration in chemistry refers to the arrangement of electrons on atomic or molecular orbital rings on an atom or molecule (or any other chemical structure for that matter). Neon’s electron configuration is 1s2 2s2 2p6, which may be explained using the following example. There are two electrons in each of the 1s, 2s, and 2p subshells, respectively. Each electron moves in an orbital on its own, in an average field formed by the orbitals of all the other electrons in the system. The principles of quantum physics dictate that for systems with only one electron, each arrangement of electrons has a distinct amount of energy. The release or acceptance of a quantum of energy can allow electrons to change their configuration under certain circumstances. Using a photon as the medium, this is accomplished. The periodic table of elements may be understood more clearly if one understands the electrical arrangement of distinct atoms. Chemical bonding can also be explained using this electrical arrangement.

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All of the elements may be grouped into four blocks on the periodic table, namely the s-block (s), p-block, d-block, and f-block. In addition to D-block elements, Transition Elements are also known. The phrase “transition element” can be used in three different ways in chemistry.

To classify an element as a d-block element, it must have electrons at the penultimate energy level and the outermost s-orbital (1-2). Group 12 metals, despite the fact that they lack electrons in the ‘d’ orbital, are termed d block elements because of their comparable chemistry to the preceding groups.

Metallic properties such as malleability and ductility; strong electrical conductivity; good tensile strength; and high tensile strength are typical of these elements. Each of the four series in the d block represents a different orbital filling up.

Why are D Block Elements transitional?

Groups 4–11 are devoted to transitional components. A partially full d subshell in the metallic state makes Scandium and Yuttrium transitional elements as well. Because Zn, Cd, and Hg have all of their d-orbitals occupied, they cannot be classified as transition elements.

As the name implies, Transition Elements represent the transition of characteristics between, s and p block elements. In other words, all transition metals are d block elements, but not all d block elements are transition metals.

Transition metals’ properties

  • The ‘d’ sub-orbitals between their (n+1) s and (n+1) p sub-orbitals are now filled with electrons.
  • Located between the s and p block elements in the periodic table.
  • The relationship between s and p-block components.

f-block elements

These elements are known as f block elements because their f orbitals are being filled up by electrons. There are electrons in the f orbitals of these elements (1 to 14), as well as in the penultimate energy level’s d orbital (0 to 1) and the outermost orbital (outermost).

F blocks have two series that correspond to filling up of 4 and 5 orbitals, respectively, Ce to Lu and Th to Lw make up the 4f and 5f series of elements, respectively. ‘f’ orbitals are filled with 14 elements in each series.

F Block Elements are categorized by their kind.

The f block’s constituents are further subdivided into:

  • First, the lanthanides, which have atomic numbers starting at 57 and ending at 72, make up the first group of elements. They do not emit radiation (except for promethium, which is radioactive).
  • Secondly, the actinides, which have atomic numbers between 89 and 103, make up the second series of elements. Most of these elements have a radioactive quality to them.

Do you know the answer of the below question?

  1. Which one of the following constitutes a set of transition elements?
  2. A) Sn,Bi, Mn
  3. B) Fe,Au, Ni
  4. C) Na,Mg, AI
  5. D) Hg, Pb, Cu

Lanthanide properties

  • Lanthanides are silvery-white soft metals.
  • When exposed to the elements, their colour fades and their brightness decreases swiftly.
  • From 1000K to 1200K, their melting points may be found (Except Samarium, 1623K).
  • In addition, lanthanides are excellent heat and electrical conductors.
  • All but Promethium are non-radioactive.
  • It has been shown that the radii of lanthanum and lutetium have decreased with time. The lanthanoid contraction is the medical term for this phenomenon.

Actinides’ characteristics

  • A silvery tinge can be seen on the Actinide elements themselves.
  • A radioactive nature may be found in several elements.
  • The reactivity of certain metals, when finely split, is enhanced.
  • From Actinium to Lawrencium, there is a drop in atomic and ionic radii. The actinoid contraction is the scientific name for this phenomenon.
  • The oxidation state is typically +3. But elements in the early half of the series are recognised for having oxidation states that are greater than those in the second half of the series.

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