p-Block Elements: Learn Properties and Characteristics - Embibe
  • Written By Akanksha P John
  • Last Modified 24-06-2022
  • Written By Akanksha P John
  • Last Modified 24-06-2022

p-Block Elements: Learn Chemical and Physical Properties of Elements

p-Block Elements: The last electron of a p-block element enters one of the three p-orbitals of the relevant shell. On the right side of the chemical periodic table, the p-block elements are commonly found. In addition to noble gauges, these include the boron, carbon, nitrogen, oxygen, and fluorine families. P-block elements are divided into six groups, each with a number between 13 and 18. A p-three subshell’s degenerate p-orbitals can each house two electrons.

Gallium, for example, has some unique and uncommon properties in p-block elements. When you grasp it in your hands, it melts into a p-block metal. Silicon, a metalloid, is used to construct p block elements. It’s a crucial step in the production of glass. Except for Helium, p-block elements are grouped in 13, 14, 15, 16, and 17.

General Characteristics of p-Block Elements: Periodic Table Blocks

In the \({\rm{p}}\)-block, the differentiating electron enters into the \({\rm{p}}\)-subshell of the outermost shell. Since the number of \({\rm{p}}\)-orbitals is three, the maximum number of electrons that can be accommodated in a \({\rm{p}}\)-subshell is six. Some general trends in the chemistry of \({\rm{p}}\)-block elements are as follows-

1. Electronic Configuration: Except for helium, the valence shell electronic configuration of \({\rm{p}}\)-block elements is \({\rm{n}}{{\rm{s}}^2}{\rm{n}}{{\rm{p}}^{1 – 6}}\). The inner core electronic configuration may differ.

2. Oxidation State: The maximum oxidation state exhibited by a \({\rm{p}}\)-block element is equal to the sum of \({\rm{ns}}\) and \({\rm{np}}\) electrons, i.e., to the total number of valence electrons. The number of possible oxidation states increases as one moves from left to right in the \({\rm{p}}\)-block. In addition to the group oxidation state, the \({\rm{p}}\)-block elements may also exhibit other oxidation states, which usually differ from the total number of valence electrons by the unit of two.

General Characteristics of p-block Elements

3. Inert Pair Effect: Due to the poor shielding effect of the d and \({\rm{f}}\)-electron in heavier elements, the pair of electrons in the valence \({\rm{s}}\)-orbital is reluctant to participate in bond formation. The lower oxidation state becomes more stable than, the higher oxidation state in lower \({\rm{p}}\)-block elements, which is known as the inert pair effect.
4. General Chemical Behaviour: Nonmetals and metalloids exist only in the \({\rm{p}}\)-block of the periodic table. The non-metallic character of elements decreases on moving down a group. The gradual change from non-metallic to metallic character affects considerably the chemistry of elements placed in a particular group.
5. Anomalous Behaviour of the First Element: The first element of each group shows an anomalous behaviour and differs from the other elements of the group in several properties.
This Behaviour is due to the following reasons-
i.) The smallest size of the first element.
ii.) High ionization enthalpy of the first element.
iii.) High electronegativity of the first element.
iv.) Absence of vacant \({\rm{d}}\)-orbitals in the valence shell of the first element.

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p-Block Group 13 Elements: The Boron Family

This group includes five elements which are boron \(\left( {\rm{B}} \right)\), aluminium \(\left( {\rm{AI}} \right)\), Gallium \(\left( {\rm{Ga}} \right)\), indium \(\left( {\rm{In}} \right)\), and thallium \(\left( {\rm{Tl}} \right)\).

General Physical Properties of Boron

i. Electronic configuration- In these elements, the differentiating electrons enter into \(‘{\rm{np}}’\) sub-shells. They possess an electronic configuration of \({\rm{n}}{{\rm{s}}^2}{\rm{n}}{{\rm{p}}^1}\).

General Physical Properties
  1. Atomic and ionic radii- The atomic and ionic radii of group \(13\) elements are smaller than those of corresponding elements of group \(2\), and the atomic and ionic radii increase on moving down the group.
  2. Density- Densities of group \(13\) elements are higher than those of group \(2\) elements, and the densities increase on moving down the group.
  3. Melting and boiling points- The melting and boiling points of these elements are much higher than group \(2\) elements. The melting points decrease from \({\rm{B}}\) to \({\rm{Ga}}\) and then increase up to \({\rm{Tl}}\).
  4. Oxidation state- As the electronic configuration is of the type \({\rm{n}}{{\rm{s}}^2}{\rm{n}}{{\rm{p}}^1}\), they are expected to exist in both \(+3\) and \(+1\) oxidation states.

General Chemical Properties of Boron

i. Action with air and water- Pure boron is unreactive. It reacts with air only at higher temperatures and does not react with water at all. \({\rm{AI}}\) reacts with air and forms a protective layer of oxide, and \({\rm{Al}}\) can decompose boiling water to produce hydrogen. \({\rm{Ga}}\) and In are not affected by air, but \({\rm{Tl}}\) forms an oxide on its surface.
ii. Hydrides- These elements do not combine directly with hydrogen, but many hydrides can be obtained by indirect methods.
iii. Halides- The elements of group \(13\) form trihalides of the type \({\rm{M}}{{\rm{X}}_3}\). In and \({\rm{TI}}\) also form \({\rm{InX}}\) or \({\rm{TIX}}\) type halides.
iv. Oxides and hydroxides- All the elements form oxides of the type \({{\rm{M}}_2}{{\rm{O}}_3}\) and hydroxides of the type \({\rm{M}}{\left( {{\rm{OH}}} \right)_3}\).

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p-Block Group 14 Elements: Carbon Family

This group includes elements which arecarbon \(\left( {\rm{C}} \right)\), silicon \(\left( {\rm{Si}} \right)\), germanium \(\left( {\rm{Ge}} \right)\), tin \(\left( {\rm{Sn}} \right)\) and lead \(\left( {\rm{Pb}} \right)\).

General Physical Properties of Carbon

i. Electronic configuration- In these elements, the differentiating electrons enter into \({\rm{np}}\) sub-shells. They possess an electronic configuration of \({\rm{n}}{{\rm{s}}^2}{\rm{n}}{{\rm{p}}^2}\).

General Physical Properties

ii. Atomic and ionic radii- The atomic and ionic radii are smaller than those of group \(13\), and they tend to increase on moving down the group.
iii. Density- The densities increase on going from \({\rm{C}}\) to \({\rm{Pb}}\).
iv. Melting and boiling points- The melting and boiling point of \({\rm{C}}\) and \({\rm{Si}}\) are much higher than other elements in the group. On moving down the group, the melting and boiling points decrease regularly.
v. Oxidation state- The common oxidation states shown by this group are \(+4\) and \(+2\).

Chemical Properties of Carbon

  1. Hydrides- The elements of this group form covalent hydrides of the type \({\rm{M}}{{\rm{H}}_4}\). Their number and ease of formation decreases down the group.
  2. Halides- The elements of group \(14\) form two types of halides- the tetrahedral type and the dihalides.
  3. Oxides- The elements of group \(14\) form two types of oxides- monoxides and dioxides.

p-Block Group 15 Elements: Nitrogen Family

This group includes elements- nitrogen \(\left( {\rm{N}} \right)\), phosphorus \(\left( {\rm{P}} \right)\), arsenic \(\left( {\rm{As}} \right)\), antimony \(\left( {\rm{Sb}} \right)\), and bismuth \(\left( {\rm{Bi}} \right)\). These elements are also known as pnictogens and their respective compounds as pniconides.

General Physical Properties of Nitrogen

i. Electronic configuration- In these elements, the differentiating electrons enter into ‘\({\rm{np}}\)’ sub-shells. They possess an electronic configuration of \({\rm{n}}{{\rm{s}}^2}{\rm{n}}{{\rm{p}}^3}\).

General Physical Properties

ii. Atomic and ionic radii- The atomic and ionic radii are smaller than those of group \(14\), and they tend to increase on moving down the group.
iii. Density- The densities increase on moving down the group.
iv. Melting and boiling point- The melting point increases from \({\rm{N}}\) to \({\rm{As}}\) then decreases and the boiling point increases regularly on moving down the group.
v. Oxidation state- The elements of this group exhibit various oxidation states that range from \(-3\) to \(+5\). Due to the inert pair effect, the stability of the \(+3\) oxidation state increases on moving down the group while the stability of the \(+5\) oxidation state decreases on moving down the group.

Chemical Properties of Nitrogen

  1. Hydrides- All of the elements in this group combine to generate covalent and pyramidal hydrides of the type \({\rm{E}}{{\rm{H}}_3}\).
  2. Halides- All elements in this group form trihalides \({\rm{M}}{{\rm{X}}_3}\), and except nitrogen all form pentahalides \({\rm{M}}{{\rm{X}}_5}\).
  3. Oxides- All the elements of this group form oxides of the type \({{\rm{M}}_2}{{\rm{O}}_3}\) and \({{\rm{M}}_2}{{\rm{O}}_5}\).

p-Block Group 16 Elements: Oxygen Family

This group includes elements- oxygen \(\left( {\rm{O}} \right)\), sulphur \(\left( {\rm{S}} \right)\), selenium \(\left( {\rm{Se}} \right)\), tellurium \(\left( {\rm{Te}} \right)\) and polonium \(\left( {\rm{Po}} \right)\). These elements are known as ore forming elements- chalcogens.

Physical Properties of Oxygen Family

i. Electronic configuration- In these elements, the differentiating electrons enter into \(‘{\rm{np}}’\) sub-shells. They possess an electronic configuration of \({\rm{n}}{{\rm{s}}^2}{\rm{n}}{{\rm{p}}^4}\).

Physical Properties

ii. Atomic and ionic radii- The atomic and ionic radii are smaller than those of group \(15\) elements, and tend to increase on moving down the group.
iii. Density- The densities increase on moving down the group.
iv. Melting and boiling points- As there is an increase in the molecular weight and van der Waals force of attraction down the group, so the melting and boiling point increases down the group.
v. Oxidation state- The elements of this group exhibit various oxidation states ranging from \(-2\) to \(+6\) except for that of oxygen. Oxygen shows an oxidation state of \(-2\) to \(+2\).

Chemical Properties of Oxygen Family

  1. Hydrides- The elements of this group form stable hydrides of the type \({{\rm{H}}_2}{\rm{E}}\), where \({\rm{E}}\) is the element of group \(16\).
  2. Halides- The elements of this group form a large number of halides of the type \({\rm{E}}{{\rm{X}}_6},\,{\rm{E}}{{\rm{X}}_4},\,{\rm{E}}{{\rm{X}}_2}\),where \({\rm{E}}\) is the element of group \(16\) and \({\rm{X}}\) is a halogen.
  3. Oxides- They form oxides \({\rm{A}}{{\rm{O}}_2}\) and \({\rm{A}}{{\rm{O}}_3}\).

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p-Block Group 17 Elements: Halogens

This group includes elements- fluorine \(\left( {\rm{F}} \right)\), chlorine \(\left( {\rm{Cl}} \right)\), bromine \(\left( {\rm{Br}} \right)\), iodine \(\left( {\rm{I}} \right)\), and astatine \(\left( {\rm{At}} \right)\).

Physical Properties of Halogens

i. Electronic configuration- In these elements, the differentiating electrons enter into \(‘{\rm{np}}’\) sub-shells. They possess an electronic configuration of \({\rm{n}}{{\rm{s}}^2}{\rm{n}}{{\rm{p}}^5}\).

Physical Properties

ii. Atomic and ionic radii- The atomic and ionic radii are smaller than those of group \(16\) elements, and tend to increase on moving down the group.
iii. Density- The density increases down the group.
iv. Melting and boiling point- The melting and boiling points increase down the group because of increase in the van der Waals forces.
v. Oxidation state- Elements such as chlorine, bromine, and iodine show \(-1\) to \(+7\) (\( + 1,\, + 3,\, + 5\), and \( + 7\)) oxidation states. Fluorine shows an oxidation state of \(-1\).

Chemical Properties of Halogen

  1. Hydrides- The elements of this group form hydrides of the type \({\rm{HX}}\). The boiling point of these hydrides are-
  2. \({\rm{HF}} > {\rm{HI}} > {\rm{HBr}} > {\rm{HCl}}\)
  3. Oxides- Halogens react with oxygen to form oxides. However, these oxides are not very steady. Halogens also form oxoanions and oxoacids.
  4. Reaction with metals- Most metals react immediately with halogens, forming metal halides as a result.

p-Block Group 18 Elements: The Noble Gases

This group contains elements- helium \(\left( {\rm{He}} \right)\), neon \(\left( {\rm{Ne}} \right)\), argon \(\left( {\rm{Ar}} \right)\), krypton \(\left( {\rm{Kr}} \right)\), xenon \(\left( {\rm{Xe}} \right)\), and radon \(\left( {\rm{Rn}} \right)\). These elements are located at the end of each period- on the extreme right-hand side of the periodic table.

Physical Properties of Noble Gases

i. Electronic configuration- The elements possess an electronic configuration of \({\rm{n}}{{\rm{s}}^2}{\rm{n}}{{\rm{p}}^6}\) except for that of helium.

Physical Properties

ii. Atomic radii- The atomic radii increases from \({\rm{He}}\) to \({\rm{Rn}}\).
iii. Density- The density of the elements increases down the group.
iv. Melting and boiling points- These elements have increasing magnitude of van der Waals force down the group, so the melting and boiling point increases from \({\rm{He}}\) to \({\rm{Rn}}\).

Chemical Properties of Noble Gases

Because of their completely filled subshells, noble gases are inert in nature.

P Block on the Periodic Table: Summary

In this article, we studied that elements in the \({\rm{p}}\)-block have their valence electron in the \({\rm{p}}\)-orbital. These elements belong to the group \(13\) to group \(18\). We studied the general trends of the \({\rm{p}}\)-block elements as well as the physical and chemical properties of individual groups. We now know the general electronic configuration of-

  1. Group \(13 – {\rm{n}}{{\rm{s}}^2}{\rm{n}}{{\rm{p}}^1}\).
  2. Group \(14 – {\rm{n}}{{\rm{s}}^2}{\rm{n}}{{\rm{p}}^2}\).
  3. Group \(15 – {\rm{n}}{{\rm{s}}^2}{\rm{n}}{{\rm{p}}^3}\).
  4. Group \(16 – {\rm{n}}{{\rm{s}}^2}{\rm{n}}{{\rm{p}}^4}\).
  5. Group \(17 – {\rm{n}}{{\rm{s}}^2}{\rm{n}}{{\rm{p}}^5}\).
  6. Group \(18 – {\rm{n}}{{\rm{s}}^2}{\rm{n}}{{\rm{p}}^6}\).

FAQs on p-Block Elements

Q.1. What are p-block elements?
Ans
: The \({\rm{p}}\)-block is the part of the periodic table that contains columns \({\rm{IIIA}}\) through \({\rm{VIIIA}}\) but not helium. There are \({\rm{35}}\,{\rm{p}}\)-block elements, all of which have valence electrons in the \({\rm{p}}\) orbital. The \({\rm{p}}\)-block elements are a collection of elements that have a wide range of properties.

Q.2. Why are they called p-block elements?
Ans
: The elements are called ({\rm{p}})-block because their valence electrons enter into the p orbital.

Q.3. What are the 17 nonmetals?
Ans
: The (17) nonmetal elements are: Hydrogen, Helium, Carbon, Nitrogen, Oxygen, Fluorine, Neon, Phosphorus, Sulphur, Chlorine, Argon, Selenium, Bromine, Krypton, Iodine, Xenon, and Radon.

Q.4. What are the properties of p-block elements?
Ans: The general properties of ({\rm{p}})-block elements are-

  1. Electronic configuration- Except for helium, the valence shell electronic configuration of ({\rm{p}})-block elements is ({\rm{n}}{{\rm{s}}^2}{\rm{n}}{{\rm{p}}^{1 – 6}}). The inner core electronic configuration may differ.
  2. Oxidation state- The number of possible oxidation states increases as one moves from left to right in the ({\rm{p}})-block. In addition to the group oxidation, the ({\rm{p}})-block elements may also exhibit other oxidation states which usually differ from the total number of valence electrons by unit of two.
  3. Inert pair effect- The lower oxidation state becomes more stable than the higher oxidation state in ({\rm{p}})-block elements, due to the inert pair effect.
  4. General chemical behaviour- The non-metallic character of elements decreases on moving down a group. The gradual change from non-metallic to metallic character affects considerably the chemistry of elements placed in a particular group.
  5. Anomalous behaviour of the first element- The first element of each group shows an anomalous behaviour and differs from the other elements of the group in several properties.

Q.5. What is the general electronic configuration of p-block elements?
Ans
: The general electronic configuration of ({\rm{p}})-block elements is ({\rm{n}}{{\rm{s}}^2}{\rm{n}}{{\rm{p}}^{1 – 6}}).

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