In view of the coronavirus pandemic, we are making LIVE CLASSES and VIDEO CLASSES completely FREE to prevent interruption in studies



p-Block Elements On The Periodic Table: All you need to know

Planet Earth has been blessed with a tremendous variety of elements, having varying physical and chemical properties. This diversity of elements made the study of individual properties of elements difficult, giving birth to the concept of a “Periodic Table”.  The Periodic Table arranges the elements in increasing order of their atomic masses. Born out of this arrangement and the three rules for filling electron orbitals (i.e. lowest energy orbitals fill first, Pauli’s Exclusion Principle and Hund’s Rule), are the four blocks of the Periodic Table namely: “s-block”, “p-block”, “d-block” and “f-block”. The name to each of the blocks is assigned based on which orbital the last electron enters into. The p-block elements lie to the rightmost of the periodic table.  Read more!

p-block elements- An overview

As explained above, the last electron in the electronic configuration enters the p-orbital of the p-block elements. Elements in Groups 13-18 of the Periodic Table are called P-block elements.  These include metals, metalloids, noble gases and halogens. Some of the commonly known elements in the P-block are:

  1. Metals: Aluminium (Al), Boron (B), Tin (Sn).
  2. Metalloids: Silicon (Si), Germanium (Ge)
  3. Noble Gases: Helium (He), Neon (Ne), Argon (Ar).
  4. Halogens: Fluorine (F), Chlorine (Cl), Bromine (Br).

Definition of p-Block

Elements having a place within the group 13 (i.e. group IIIA) to group 17 (i.e. group VIIA) of the periodic table alongside the group 18 i.e. the zero group elements together frame the p-block of the periodic table.

Position of p-Block Elements in the Periodic Table

In the elements of p-block, the last electron enters the furthest p orbital. They have 3 to 8 electrons in the peripheral shell. As we realize that the quantity of p orbitals is three and, therefore, the most extreme number of electrons that can be obliged in an arrangement of p orbitals is six. Consequently, there are six groups of p-block elements in the periodic table numbering from 13 to 18.

First group: group IIIA called as Boron group

Second group: group IVA called as Carbon group.

Third group: group VA called as Nitrogen group.

Fourth group: group VIA called as Chalcogens.

Fifth group: group VIIA called as Halogens.

Sixth group: zero group or group 18 called as Inert or Noble gasses group.

In the p-block, all the three sorts of elements are available, i.e. the Metals, Non-Metals, and Metalloids.The crisscross line in the p-block isolates every one of the elements that are metals from those that are non-metals. Metals are found on the left of the line, and non-metals are those on the right. Along the line, we discover the metalloids. Because of the nearness of a wide range of elements, the p-block demonstrates a great deal of variety in properties.

Elements in the p-block of the Periodic Table

The elements in the p-block of the periodic table comprises of a wide range of elements i.e. metals, non-metals and metalloids.

          Metals            Non-Metals Metalloids
Aluminium Helium Boron
Gallium Carbon Silicon
Indium Nitrogen Germanium
Thallium Oxygen Arsenic
Tin Fluorine Antimony
Lead Neon Tellurium
Phosphorous Polonium
Sulphur Astatine
Chlorine
Argon
Selenium
Bromine
Krypton
Iodine
Xenon
Radon

 

Let us now go over each group of p-block elements one by one.

Group-13 Elements

  • Group-13 elements belong to the first group of p-block elements and include Boron (B), Aluminium (Al), Gallium (Ga), Indium (In) and Thallium (Tl).
  • Boron is the only metalloid in the group while the rest of the elements are metals. Gallium is liquid at temperatures over 30oC.
  • They contain three electrons in the outer most shell i.e. a filled s-orbital and one electron in the p-orbital. (ns2np1)

General Physical and Chemical Properties

  • Atomic Radius and density increases down the group with Thallium (Tl) having the largest atomic radius and highest density. (**Atomic radius of gallium is less than Aluminium due to poor shielding effect of d-orbital electrons.)
  • First Ionization Energy decreases down the group. (except Thallium)
  • Boiling Point decreases down the group.
  • Electronegativity decreases from Boron to Aluminium, but then increases marginally. This discrepancy is due to aberrant trends in atomic size.
  • Sum of first three ionization enthalpies decreases considerably from boron to aluminium, but then increases due to poor shielding effect of intervening d- and f- orbital electrons.
  • The relative stability of the +1 oxidation state increases from Aluminium to Thallium.
  • These are electron deficient elements, hence act as good Lewis acids. The tendency to behave as Lewis acids decreases down the group.
  • Oxide of boron is acidic, oxides of Aluminium and gallium are amphoteric, while oxides of indium and thallium are basic in nature.
  • Boron and Aluminium react at high temperatures with oxygen and nitrogen to form oxides and nitrides respectively.
  • Boron is nonreactive at moderate temperatures to acids and alkalis, whereas Aluminium reacts with both acids and bases.

Uses

  • Boron, in the form of borax (Na2B4O7.10H2O), is used in household cleaning products, as a pH buffer for gel electrophoresis, as flux for soldering and in laboratory tests for transition metals due to the characteristic colours of their metaborates when exposed to flame.
  • Orthoboric acid is used in the manufacture of fibreglass, LCD display screen glass and as a dry lubricant for carom boards.
  • Aluminium is used in the manufacture of aircraft bodies, food packaging materials in the form of aluminium foil, pipes, tubes, coins and electrical wires (due to high electrical conductivity).
  • Lithium Aluminium Hydride (LiAlH4) and Sodium borohydride (NaBH4) are potent reducing agents used in organic chemistry.

Group-14 Elements

  • Group-14 elements include Carbon (C), Silicon (Si), Germanium (Ge), Tin (Sn) and Lead (Pb).
  • Carbon is a non-metal, silicon and germanium are metalloids, tin and lead are metals.
  • They contain four electrons in the outer most shell i.e. a filled s-orbital and two electrons in the p-orbital. (ns2np2).

General Physical and Chemical Properties

  • There is a considerable increase in covalent radius from carbon to silicon, but a small increase from silicon to lead. This is due to poor shielding effect of completely filled d and f orbitals.
  • First ionization enthalpy is higher than the corresponding members of group 13. Ionisation enthalpy generally decreases down the group. Discrepancies in the trend are also due to poor shielding effect of d and f orbital electrons.
  • Electronegativity from silicon to lead is almost same, but higher than the corresponding group 13 members.
  • Boiling point decreases down the group from silicon to lead.
  • Melting and Boiling points are higher than the corresponding group 13 members.
  • Tendency to show +2 oxidation state increases from germanium to lead. Stability of +4 oxidation state decreases down the group.
  • Lead is stable in +2 oxidation state and acts as an oxidising agent in +4 oxidation state.
  • Presence of d-orbital in elements apart from carbon increases their tendency to form complexes by accepting electron pairs from donors.
  • Two types of oxides are formed, on heating with oxygen- monoxides and dioxides. Dioxides tend to be more acidic than monoxides.
  • Acidic nature of dioxides decreases down the group; tin and lead dioxide is amphoteric.
  • Stability of dihalides increases down the group, whereas stability of tetrahalides decreases down the group.
  • Carbon has a unique property of forming long chains by linking with other carbon atoms. This is called catenation. Tendency of catenation decreases down the group (Lead does not show catenation.)
  • Carbon also has unique ability to form pπ– pπ multiple bonds with itself and with other atoms of small size and high electronegativity.
  • Due to catenation and formation of pπ– pπ multiple bonds, allotropic forms of carbon, namely graphite, diamond and fullerenes exist.

Uses

  • Carbon, in form of graphite fibres, is used to make tennis racquets and aircrafts. Graphite is used as an electrode in batteries.
  • Activated charcoal is used in water purification and removal of poisonous gases.
  • Diamond is used in jewellery and in cutting equipment.
  • Silicon is used in electronics and manufacture of cement.
  • Germanium is used in synthesis of polyethylene terephthalate.
  • Tin is used to make alloys and solder, used for making connections in electrical circuits.
  • Lead is used in radiation shields.

Group-15 Elements

  • Group-15 elements include Nitrogen (N), Phosphorous (P), Arsenic (As), Antimony (Sb) and Bismuth (Bi).
  • Nitrogen and Phosphorous are non-metals, arsenic and antimony are metalloids while bismuth is a metal.
  • They contain five electrons in the outer most shell i.e. a filled s-orbital and three electrons in the p-orbital. (ns2np3). The p-orbital is half-filled, making it more stable.

General Physical and Chemical Properties

  • Covalent and ionic radii increase in size down the group. The lack of regular trend is due to poor shielding effect of d and f orbitals.
  • Ionisation enthalpy decreases down the group due to increase in atomic size, and is higher than the corresponding group 15 members due to extra stability of half-filled p orbitals.
  • Electronegativity decreases down the group.
  • Metallic character increases down the group.
  • Boiling point increases up to arsenic and then decreases up to bismuth.
  • Allotropy is seen in all elements except nitrogen.
  • Stability of -3 and +5 oxidation state decreases down the group.
  • Nitrogen can form multiple pπ– pπ bonds, whereas phosphorous and arsenic can form dπ– pπ bonds.
  • Oxides formed are of two types with different oxidation states of the element – +3 and +5.
  • Oxides of higher oxidation state are more acidic and acidic character of these oxides decreases down the group.
  • All elements react with metals and possess -3 oxidations states in their respective compounds.

Uses

  • Nitrogen is used as a coolant, to make fertilizers, plastics and explosives. It is also used in cryopreservation, pharmaceuticals and X-ray detectors.
  • Phosphorous is used in fertilizers along with nitrogen, in making matches to light fires, softening hard water, and military applications like smoke bombs.
  • Arsenic is used in semiconductors in the form of gallium arsenide. Arsenic-lead alloys are used to manufacture bullets.
  • Antimony is used as a dopant in semiconductors.
  • Bismuth is used as a catalyst to make acrylic fibres and in cosmetics.

Group-16 Elements

  • Group-16 elements include Oxygen (O), Sulphur (S), Selenium (Se), Tellurium (Te) and Polonium (Po).
  • Oxygen and Sulphur are non-metals, selenium and tellurium are metalloids, whereas polonium is a metal.
  • They contain six electrons in the outer most shell i.e. a filled s-orbital and four electrons in the p-orbital. (ns2np4).

General Physical and Chemical Properties

  • Atomic radii, ionic radii, metallic character, melting and boiling points increase down the group.
  • Ionization enthalpy decreases down the group due to increase in size, but is less than the corresponding elements of Group-15. (Extra stable Half-filled p-orbitals)
  • Electronegativity decreases down the group.
  • All elements exhibit allotropy.
  • Stability of -2 and +6 oxidation states decreases down the group. Oxygen can show only -2 oxidation state, except in case of OF2 (+2 oxidation state).
  • Stability of +4 oxidation state increases down the group due to inert pair effect.
  • Acidic character of hydrides and their reducing power increases down the group. (Except H2O).
  • Reducing property of oxides decreases down the group and their oxides are acidic in nature.
  • These can form either dihalides or tetrahalides or hexahalides. Only hexafluorides are stable.

Uses

  • Oxygen is used as liquid fuel in rockets, in oxy-acetylene flames used for welding, in smelting iron into steel and as a breathing gas by organisms on the planet.
  • Sulphur, in the form of sulphuric acid is used in manufacture of fertilizers, paints, dye and storage batteries, in petroleum refining, cleansing metals and as a laboratory reagent. Sulphur is also used in the vulcanization of rubber.
  • Selenium is used in manganese electrolysis and in alloys with bismuth.
  • Tellurium is used in solar panels.

Group-17 Elements

  • Group-17 elements include Fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I) and Astatine (At).
  • They contain seven electrons in the outer most shell i.e. a filled s-orbital and five electrons in the p-orbital. (ns2np5).

General Physical and Chemical Properties

  • They have the smallest atomic radii in their respective periods. Atomic, Ionic radii, melting and boiling points increase down the group, as expected.
  • Ionisation enthalpy, electronegativity, oxidising power, affinity to hydrogen, ionic character of metal halides, all decrease down the group.
  • Bond dissociation enthalpy decreases down the group, however due to large electron-electron repulsion in fluorine, its bond dissociation enthalpy is close to that of chlorine.
  • Oxidation states exhibited are -1, +1, +3, +5 and +7. Fluorine exists in -1 oxidation state only.
  • Acidic strength of hydrides and stability of oxides increases down the group (I>Br>Cl).

 Uses

  • Fluorine is used to fluorinate uranium and polonium, used as nuclear fuel in reactors. It is also used in PET imaging and PTFE synthesis.
  • Chlorine is used as a disinfectant, in bleaching wood pulp for paper manufacture, in extraction of gold, manufacture of dyes and organic solvents etc.
  • Bromine is used in photography, in flame retardants, and synthesis of brominated polymers.
  • Iodine is used as a laboratory reagent for testing ammonium ions (Nessler’s reagent), as disinfectant, for cloud seeding etc.

 

Group-18 elements

  • Group-18 elements constitute the last group of p-block elements and include Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe) and Radon (Rn).
  • Helium is an exception as it does not have p-orbitals. All the elements in the group are gases.
  • They contain eight electrons in the outer most shell i.e. a filled s-orbital and a completely filled p-orbital, with the exception of Helium (ns2np6).

General Physical and Chemical Properties

  • Exhibit very high ionization enthalpies due to high stability and it decreases down the group.
  • Atomic radii, melting and boiling points increase down the group.
  • Only xenon reacts with fluorine and oxygen to form fluorides and oxides respectively.

Uses

  • Helium is used in filling hot air balloons and in superconducting magnets.
  • Neon is used in bulbs and lights for advertisement and display purposes.
  • Argon is used to provide inert atmosphere for metallurgical reactions.

That’s all on p-block elements for now. Hope the article kept the promise it made. To know all about d-block elements click here. If you have anything to add to the p-block elements, do leave it in the comments’ section. Till then, Toppr wishes you all the best!

What will your
All India Rank be?

Compete with lakhs of students across India on tests created by the best teachers in India.

+91
No thanks.

Request a Free 60 minute counselling session at your home

Please enter a valid phone number
  • Happy Students

    7,829,648

    Happy Students
  • Questions Attempted

    358,177,393

    Questions Attempted
  • Tests

    3,028,498

    Tests Taken
  • Doubts Answered

    3,020,367

    Doubts Answered