Chemistry · Class 11 Science
Ch 7p-Block Elements (Groups 13-14) — Class 11 Chemistry, concept-first.
The p-block of the periodic table consists of Groups 13 through 18 — the elements in which the differentiating (last-entering) electron occupies a -orbital of the outermost shell. Helium, though its configuration is , is conventionally placed with the noble gases of Group 18 rather than the -block.
Key concepts
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General Trends in the p-Block Elements
p-Block groups share one organising idea: the group oxidation state equals the number of valence electrons (Table 11.1), yet almost every group's heavier members increasingly prefer an oxidation state two units LOWER tha…
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Chapter contents
The NCERT structure, section by section. Open a section to see its questions, then read the concept-first solution.
General Introduction to p-Block Elements
The p-block of the periodic table consists of Groups 13 through 18 — the elements in which the differentiating (last-entering) electron occupies a -orbital of the outermost shell.
Group 13 Elements: The Boron Family — General Trends
Group 13, the boron family, comprises boron (B), aluminium (Al), gallium (Ga), indium (In) and thallium (Tl), all sharing the general outer-shell configuration .
Boron Oxide and Boric Acid
Boron's principal oxide, boron oxide (), is formed by strongly heating boric acid or boron itself in air/oxygen.
Borax
Borax, , is by far the most important naturally occurring borate mineral and the starting point for almost all commercial boron chemistry, including the preparation of boric acid and boron oxide descr…
Diborane, B2H6
Diborane, , is the simplest and most important boron hydride, and is the standard textbook illustration of electron-deficient bonding.
Aluminium and its Compounds
Aluminium is the third member of Group 13 and, unlike boron, is a genuine metal — the most abundant metal in the Earth's crust.
Group 14 Elements: The Carbon Family — General Trends
Group 14, the carbon family, comprises carbon (C), silicon (Si), germanium (Ge), tin (Sn) and lead (Pb), sharing the general outer-shell configuration .
Catenation and Allotropes of Carbon
Carbon's exceptionally strong catenation, introduced in the previous section, gives rise to several structurally very different allotropes — forms of the same element differing only in how its atoms a…
Oxides of Carbon: CO and CO2
Carbon forms two important gaseous oxides, carbon monoxide and carbon dioxide, whose structures and chemical behaviour differ sharply.
Silicon Tetrachloride (SiCl4)
Silicon tetrachloride, , is the most important and best studied of the silicon halides. Like carbon tetrachloride, it is a simple, symmetric tetrahedral molecule, with the silicon atom hybridised and…
Silicates
Every silicate mineral — however chemically complex it may appear — is built from just one repeating structural unit: the tetrahedron, in which a central silicon atom is hybridised and covalently bond…
Zeolites
Zeolites are a special, industrially and environmentally important class of three-dimensional framework silicates (see the previous section) in which a fraction of the framework's silicon atoms have b…
Group 13 vs Group 14 — Oxidation-State and Trend Reference Table
More questions
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- Example 1State the general valence-shell electronic configuration of the p-block elements, and write out the specific configurations for the outermos…Free
- Example 2Boron behaves quite differently from the rest of the Group 13 elements (Al, Ga, In, Tl), even though all share the outer configuration $ns^2…Free
- Example 3What is the inert pair effect? Using this idea, explain why thallium is more stable in the $+1$ oxidation state than in the $+3$ state, even…Free
- Example 4Boric acid, $\text{B(OH)}_3$, is described as a weak monobasic acid, yet it does not release a proton like a typical Brønsted acid. Explain…Preview
- Example 5Describe the structure of the tetraborate ion present in borax, $\text{Na}_2\text{B}_4\text{O}_7\!\cdot\!10\text{H}_2\text{O}$, in terms of…Preview
- Example 6Diborane, $\text{B}_2\text{H}_6$, has only 12 valence electrons but must account for 8 B–H connections. Describe its structure, distinguishi…Preview
- Example 7Write a balanced equation for the laboratory preparation of diborane from boron trifluoride and lithium hydride, and state one characteristi…Preview
- Example 8Aluminium is described as an amphoteric metal. Write balanced equations for its reaction with (a) dilute hydrochloric acid and (b) aqueous s…Preview
- Example 9Give the equation for the preparation of lithium aluminium hydride, $\text{LiAlH}_4$, from lithium hydride and aluminium chloride. Why is $\…Preview
- Example 10Show, with balanced equations, that aluminium oxide $\text{Al}_2\text{O}_3$ is amphoteric. Name two everyday or industrial uses of $\text{Al…Preview
- Example 11Group 14 elements show two characteristic oxidation states, $+2$ and $+4$. State which is more stable for carbon and silicon, which becomes…Preview
- Example 12Catenation — the ability of an element to form chains/rings of like atoms bonded to each other — is far stronger in carbon than in the rest…Preview
- Example 13Compare the crystal structures of diamond and graphite. In your answer, describe the hybridisation of carbon in each, explain why diamond is…Preview
- Example 14What is a fullerene? Describe the structure of $\text{C}_{60}$ (buckminsterfullerene), and explain how graphene is related to graphite. Name…Preview
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- Q15Explain why carbon monoxide is highly toxic even though it is produced in only small amounts by incomplete combustion. What is its effect on…Free
- Q16Carbon monoxide acts as a good reducing agent in metallurgy. Write the equation for its use in reducing iron(III) oxide in the blast furnace…Free
- Q17Describe the shape of the $\text{CO}_2$ molecule and its hybridisation. Write the equation for the reaction of $\text{CO}_2$ with lime water…Free
- Q18Draw/describe the structure of silicon tetrachloride, $\text{SiCl}_4$. Write a balanced equation for its hydrolysis, and name the products f…Preview
- Q19Explain why $\text{SiCl}_4$ is readily hydrolysed by water while $\text{CCl}_4$ is not, even though both molecules are tetrahedral $\text{MC…Preview
- Q20Describe the basic structural unit found in all silicates. How do orthosilicates, chain silicates and sheet silicates differ in the way this…Preview
- Q21A chain (pyroxene-type) silicate has the repeating formula $(\text{SiO}_3)_n^{2n-}$. Starting from the $\text{SiO}_4^{4-}$ tetrahedron, expl…Preview
- Q22What are zeolites? Describe their general structure and explain how their negatively charged aluminosilicate framework is charge-balanced.Preview
- Q23Explain how zeolites are used to soften hard water, and how a shape-selective zeolite catalyst such as ZSM-5 is used in the petrochemical in…Preview
- Q24Across the p-block, describe the general trend in (a) atomic size, (b) ionisation enthalpy, and (c) metallic character on moving down any on…Preview
- Q25Explain, with reference to atomic size and ionisation enthalpy, why gallium's first ionisation enthalpy is anomalously close to that of alum…Preview
- Q26Describe the structure of boron oxide, $\text{B}_2\text{O}_3$, and explain how it is related to boric acid on heating. Give the sequence of…Preview
- Q27What is the borax-bead test used for in qualitative inorganic analysis? Briefly describe what happens when borax is strongly heated and the…Preview
- Q28List two major industrial uses each of aluminium metal and of $\text{LiAlH}_4$, and explain briefly why aluminium's natural oxide layer make…Preview