Latest questions in this category.
Second ionization enthalpy for group 2 elements involves removing an electron from X+ (noble gas-like). Be⁺ (smallest size) has the highest value due to greater nuclear attraction.
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Electronic Configuration and Types of Elements - s p d f Blocks
Boiling points of group 16 hydrides increase with molecular weight, except for H₂O (hydrogen bonding). H₂S has the lowest boiling point among H₂O, H₂S, H₂Se, and H₂Te due to weak intermolecular forces.
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Electronic Configuration and Types of Elements - s p d f Blocks
Fourth ionization enthalpy peaks when removing an electron from a stable X³⁺ ion. Al (after losing three electrons, becomes Al³⁺ with 1s² 2s² 2p⁶) has the highest value in period 3.
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Electronic Configuration and Types of Elements - s p d f Blocks
Electronegativity increases across a period. In period 4 (K to Kr), Br (group 17) has the highest electronegativity among K, Ca, and Br.
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Electronic Configuration and Types of Elements - s p d f Blocks
Metallic character decreases across period 3 due to increasing nuclear charge. Order: Cl < S < P < Si.
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Electronic Configuration and Types of Elements - s p d f Blocks
Amphoteric oxides, formed by elements near the metal-non-metal boundary, react with both acids and bases. As₂O₃ (group 15) is amphoteric, unlike Li₂O (basic), SO₂ (acidic), or CO (neutral).
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Electronic Configuration and Types of Elements - s p d f Blocks
This configuration (Z=24) corresponds to Cr, an exception due to the stability of half-filled 3d⁵, unlike Mn (3d⁵ 4s²), Fe (3d⁶ 4s²), or Co (3d⁷ 4s²).
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Electronic Configuration and Types of Elements - s p d f Blocks
The +6 oxidation state is most stable for S (e.g., in SO₃) due to its balance of size and electronegativity, unlike O, Se, or Te, where it’s less common or stable.
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Electronic Configuration and Types of Elements - s p d f Blocks
The configuration 4s² 4p³ corresponds to As (Z=33, period 4, group 15), with full configuration 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p³.
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Electronic Configuration and Types of Elements - s p d f Blocks
Alkaline earth metals belong to group 2. Ca is in group 2, while B (group 13), N (group 15), and Cl (group 17) are not.
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Electronic Configuration and Types of Elements - s p d f Blocks
In group 14, CO₂ (from C) is covalent and acidic, reacting with bases to form carbonates, unlike SiO₂ (covalent but less acidic), GeO₂, or SnO₂ (amphoteric).
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Electronic Configuration and Types of Elements - s p d f Blocks
For isoelectronic species (18 electrons), polarizing power increases with charge and decreases with size. Sc³⁺ (Z=21, +3) has the highest polarizing power compared to K+, Ca²⁺, or Cl⁻.
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Electronic Configuration and Types of Elements - s p d f Blocks
