Latest questions in this category.
Be (group 2, period 2) shows a diagonal relationship with Al (group 13, period 3) due to similar size and electronegativity, unlike Mg, Ca, or B.
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Anomalous Properties and Second Period and Chemical Reactivity
In period 4 d-block (Sc to Zn), density increases with atomic mass and decreases with volume. Cu (group 11) has the highest density due to its compact structure.
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Anomalous Properties and Second Period and Chemical Reactivity
Total electrons = 11, corresponding to Na (period 3, group 1). Others: Mg (12 electrons), Al (13 electrons), Ne (10 electrons).
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Anomalous Properties and Second Period and Chemical Reactivity
Cr (Z=24) has an exceptional configuration (3d⁵ 4s¹) due to the stability of a half-filled 3d subshell, unlike Sc (3d¹ 4s²), Mn (3d⁵ 4s²), or Fe (3d⁶ 4s²).
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Anomalous Properties and Second Period and Chemical Reactivity
Thermal stability of group 15 hydrides decreases down the group due to weaker X-H bonds. BiH₃ (Bi, largest) has the lowest stability among NH₃, PH₃, AsH₃, and BiH₃.
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Anomalous Properties and Second Period and Chemical Reactivity
Boiling point increases down group 17 due to stronger London dispersion forces with larger size. I (period 5) has the highest boiling point among F, Cl, Br, and I.
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Anomalous Properties and Second Period and Chemical Reactivity
Melting point decreases down group 1 due to weaker metallic bonding. Cs (group 1, period 6) has the lowest melting point among Li, Na, and Cs.
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Anomalous Properties and Second Period and Chemical Reactivity
Diagonal relationships minimize electronegativity differences. Be (1.5, period 2) and Al (1.5, period 3) have nearly identical values, unlike other pairs with larger gaps.
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Anomalous Properties and Second Period and Chemical Reactivity
Group 1 elements (alkali metals) have one valence electron, with outer configuration ns¹.
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Anomalous Properties and Second Period and Chemical Reactivity
B (group 13) has a covalent network structure, giving it an exceptionally high melting point compared to Al, Ga, or In, which are metallic.
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Anomalous Properties and Second Period and Chemical Reactivity
Boiling point increases down group 16 due to stronger intermolecular forces. Te (period 5, solid) has the highest boiling point among O₂, S₈, Se, and Te.
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Anomalous Properties and Second Period and Chemical Reactivity
Atomic radius decreases across a period due to increasing nuclear charge. Among Li, B, N, and F, F (group 17, period 2) has the smallest radius.
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Anomalous Properties and Second Period and Chemical Reactivity
