35 public questions tagged with this topic.
Cr has an anomalous configuration due to the stability of half-filled d orbitals: [Ar] 3d 5 4s 1 .
Ref: NCERT Class 12 Chemistry > Chapter 4: d and f Block Elements > Topic: General Properties of d-Block - Electronic Configuration and Trends
For isoelectronic species (K+, Ca²⁺, Sc³⁺, all with 18 electrons), radius decreases with increasing nuclear charge. Sc³⁺ (Z=21) has the smallest radius.
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Electron Gain Enthalpy and Electronegativity and Valency
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
The Balmer series lies in the visible region.
Ref: NCERT Class 11 Chemistry > Chapter 2: Structure of Atom > Topic: Shapes of Orbitals - s p d f and Nodes and Radial Probability
One specific 4p orbital holds 2 electrons.
Ref: NCERT Class 11 Chemistry > Chapter 2: Structure of Atom > Topic: Shapes of Orbitals - s p d f and Nodes and Radial Probability
Maximum electrons = 2n² = 18.
Ref: NCERT Class 11 Chemistry > Chapter 2: Structure of Atom > Topic: Shapes of Orbitals - s p d f and Nodes and Radial Probability
For l=2 (d subshell), orbitals = 5. Electrons = 5×2 = 10.
Ref: NCERT Class 11 Chemistry > Chapter 2: Structure of Atom > Topic: Shapes of Orbitals - s p d f and Nodes and Radial Probability
The azimuthal quantum number l determines the shape of an orbital.
Ref: NCERT Class 11 Chemistry > Chapter 2: Structure of Atom > Topic: Quantum Numbers - Principal Azimuthal Magnetic Spin
For n=3, l max = 2. l=3 is invalid.
Ref: NCERT Class 11 Chemistry > Chapter 2: Structure of Atom > Topic: Quantum Numbers - Principal Azimuthal Magnetic Spin
The magnetic quantum number mₗ determines the orientation of an orbital.
Ref: NCERT Class 11 Chemistry > Chapter 2: Structure of Atom > Topic: Quantum Numbers - Principal Azimuthal Magnetic Spin
n=6. E₆ = -2.18×10⁻¹⁸/36 = -6.056×10⁻²⁰ J.
Ref: NCERT Class 11 Chemistry > Chapter 2: Structure of Atom > Topic: Quantum Numbers - Principal Azimuthal Magnetic Spin
rₙ = r₁ × n². r₃/r₁ = 9.
Ref: NCERT Class 11 Chemistry > Chapter 2: Structure of Atom > Topic: Quantum Numbers - Principal Azimuthal Magnetic Spin
