Flashcards for NEET Chemistry - The p-Block Elements

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The p-Block Elements

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The p-Block Elements

Group 15 Elements

N, P, As, Sb, Bi, Mc

The valence shell electronic configuration is ns²np³

N and P – non-metals

As and Sb – metalloids

Bi and Mc (moscovium) – metals

Common oxidation states are -3, +3 and +5

Hydrides of Group 15 Elements

NH3 has higher melting and boiling points than PH₃ due to hydrogen bonding

NH₃ is a mild reducing agent and BiH₃ is the strongest reducing agent

Basicity order – NH₃ > PH₃ > AsH₃ > SbH₃ > BiH₃

Halides of Group 15 Elements

Pentahalides are more covalent than trihalides

Nitrogen does not form pentahalide due to the absence of the d-orbitals in its valence shell

Ammonia

Prepared commercially by Haber’s process

It is trigonal pyramidal

It is a Lewis base due to the presence of a lone pair of electrons

White Phosphorus

P₄ is tetrahedral, shows chemiluminescence

Less stable due to angular strain (60°)

Catches fire in the air

Red Phosphorus

It is polymeric, contains chains of P₄ tetrahedra

Obtained by heating white phosphorus at 573 K

Black Phosphorus

α-Black phosphorus – it is prepared by heating red phosphorus at 803 K

β-Black phosphorus – it is prepared by heating white phosphorus at 473 K

Phosphine

PH₃

Weakly basic

Prepared by heating white phosphorus with

concentrated NaOH solution

Used in Holme’s signals and in smoke screens

Phosphorus Trichloride (PCl₃)

sp³ hybridisation, pyramidal shape

Preparation

P₄ + 6Cl₂ → 4PCl₃

P₄ + 8SOCl₂ → 4PCl₃ + 4SO₂ + 2S₂Cl₂

Phosphorus Pentachloride (PCl₅)

Trigonal bipyramidal structure

Two axial P–Cl bonds are longer than equatorial bonds

Preparation

P₄ + 10Cl₂ → 4PCl₅

P₄ + 10SO₂Cl₂ → 4PCl₅ + 10SO₂

Group 16 Elements (Chalcogens)

O, S, Se, Te, Po, Lv

The valence shell electronic configuration is ns²np⁴

The stability of the -2 oxidation state decreases down the group

Oxygen is exceptionally small and the most electronegative element after fluorine

Oxides

Generally, metallic oxides are basic, and non-metal oxides are acidic

Al₂O₃ – amphoteric

CO, NO and N₂O – neutral oxides

Group 17 Elements (Halogens)

F, Cl, Br, I, At, Ts

The valence shell electronic configuration is ns²np⁵

F and Cl are gases, Br is a liquid, and I is a solid

The most common oxidation state is –1, Cl, Br, and I also exhibit + 1, + 3, + 5 and + 7 oxidation states

Group 18 Elements (Noble gases)

He, Ne, Ar, Kr, Xe, Rn, Og

The valence shell electronic configuration is ns²np⁶

Helium, neon, argon, krypton, xenon, radon and oganesson

Xenon-fluorine Compounds

XeF₂ – Linear

XeF₄ – Square planar

XeF₆ – Distorted octahedral

Also check:

• NEET Chemistry Syllabus
• NEET Chemistry Important Topics
• NEET Chemistry MCQs
• How to Score 160 Plus in NEET Chemistry