Ch 2p-Block Elements-I — Class 12 Chemistry, concept-first.

Last year you learned to sort every element into one of four blocks -- s, p, d or f -- and studied the s-block elements and their compounds in detail.

We have already learnt that an element's properties largely depend on its electronic configuration, size, ionisation enthalpy and electronegativity.

Every p-block element shares the general outer electronic configuration ns² np¹⁻⁶: all elements of a given group have an identical outer-shell configuration and differ from each other only in the prin…

Metallic (electropositive) character is an element's tendency to lose electrons and form a cation; it tracks directly with ionisation energy -- the lower the ionisation energy, the more readily an ele…

On descending any group of the periodic table, atomic radius generally increases, and ionisation enthalpy -- the energy needed to remove the outermost electron -- generally falls in step with it.

Descending group 13, electronegativity first falls from boron to aluminium (as expected from the increasing atomic size), then rises again -- only marginally -- at gallium, after which it stays essent…

Across every group of the p-block, the first member differs noticeably from the rest of its own family -- a pattern traceable to three compounding factors: the first member's exceptionally small size,…

Just as the alkali and alkaline earth metals show the group oxidation states +1 and +2 (corresponding to the total number of valence electrons they carry), the p-block elements too generally show thei…

Some elements can exist in more than one distinct crystalline or molecular form while remaining in the same physical state -- carbon, for instance, exists as both diamond and graphite, two solids with…

Group 13, the boron group, consists of boron, aluminium, gallium, indium and thallium. Boron -- the only non-metal of the group -- sits at one extreme of the family's chemistry, forming an unusually r…

Boron occurs in nature almost entirely as borate minerals, its two chief ores being borax, Na₂[B₄O₅(OH)₄].8H₂O, and kernite, Na₂[B₄O₅(OH)₄].2H₂O.

Table 2.3 tabulates the core physical properties of the five group 13 elements. All five are solids at 293 K.

Boron is the sole non-metal of group 13 and is comparatively unreactive at ordinary temperature, though it becomes reactive at high temperatures.

Borax is the sodium salt of tetraboric acid, formulated Na₂B₄O₇.10H₂O.

Boric acid, H₃BO₃ or B(OH)₃, can be extracted from either borax or colemanite.

Diborane, B₂H₆, is the simplest of the boron hydrides (boranes).

Boron trifluoride, BF₃, is the boron trihalide of greatest chemical importance.

Aluminium chloride, AlCl₃, is the most industrially important aluminium halide.

Alums are a family of double salts named after the archetype, potash alum, potassium aluminium sulphate [K₂SO₄.Al₂(SO₄)₃.24H₂O].

Group 14, the carbon group, consists of carbon, silicon, germanium, tin and lead. Carbon -- the lightest and only true non-metal of the group -- stands apart from every other group 14 element in its e…

Carbon occurs in native (free) form as graphite. In combined form, it occurs in vast quantities trapped within the earth as coal and crude oil (the fossil fuels), and locked into carbonate rocks such…

Table 2.4 tabulates the core physical properties of the five group 14 elements. All five are solids at 293 K. Atomic number rises from 6 (carbon) to 82 (lead).

Catenation is the ability of an element to bond with itself, building up chains of atoms. For an element to catenate well, four conditions have to be met: (i) its valency must be at least two, (ii) it…

Carbon exists in many distinct allotropic forms, the two most familiar being graphite and diamond; the more recently characterised graphene, fullerenes and carbon nanotubes round out the list.

Carbon monoxide (CO) is one of the two important oxides of carbon.

Carbon dioxide (CO₂) occurs in nature both free (about 0.03% of air by volume) and combined, as calcium and magnesium carbonate rock.

Silicon tetrachloride (SiCl₄) is the most important of silicon's simple halides.

Silicones (polysiloxanes) are organosilicon polymers of general empirical formula (R₂SiO) -- named 'silicones' because this formula formally resembles that of a ketone, R₂CO.

A silicate is any mineral built from [SiO₄]⁴⁻ tetrahedra -- one silicon atom at the centre, four oxygen atoms at the corners -- linked together in one of several characteristic patterns.

Zeolites are three-dimensional crystalline solids containing aluminium, silicon and oxygen arranged in a regular three-dimensional framework.

- The elements in which the last electron enters a 'p' orbital constitute the p-block elements. - p-Block elements share the general electronic configuration ns² np¹⁻⁶; elements of a group share the s…

This is the textbook's own end-of-chapter evaluation for the unit, testing material from both halves of the chapter -- general p-block trends (Section 2.1) and the detailed chemistry of the Group 13 b…

Sample papers and previous-year board questions for this subject.