5 public questions tagged with this topic.
In period 4 d-block (Sc to Zn), ionization enthalpy increases across due to increasing nuclear charge, with Zn (3d¹⁰ 4s²) having the highest due to its full d-subshell stability.
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Periodic Trends - Atomic Radii Ionic Radii and Ionization Enthalpy
d-block elements (groups 3–12) have electrons filling (n-1)d orbitals, with outer configuration (n-1)d¹⁻¹⁰ ns⁰⁻².
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Modern Periodic Law and Present Form - Long Form Periodic Table
In period 4 d-block (Sc to Zn), boiling point peaks with strong metallic bonding. Cr (group 6) has the highest boiling point due to its 3d⁵ 4s¹ configuration and maximum unpaired electrons enhancing bonding.
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 period 5 d-block (Y to Cd), melting point peaks with strong metallic bonding. Mo (group 6, 4d⁵ 5s¹) has the highest melting point due to maximum unpaired electrons.
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Electron Gain Enthalpy and Electronegativity and Valency
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
