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प्रश्न
Explain the anomalous behaviour of chromium.
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उत्तर
- Chromium (Cr) has atomic number 24.
- Its expected electronic configuration is 1s2 2s2 2p6 3s2 3p6 4s2 3d4.
- The 3d orbital is less stable, as it is not half-filled.
- Due to inter-electronic repulsion forces, one 4s electron enters into the 3d orbital. This makes the 4s and 3d orbitals half-filled, which gives extra stability, and the electronic configuration of Cr becomes 1s2 2s2 2p6 3s2 3p6 4s1 3d5.
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संबंधित प्रश्न
Choose the correct option.
“No two electrons in the same atoms can have identical set of four quantum numbers”. This statement is known as -
State and explain Pauli’s exclusion principle.
Write orbital notations for the electron in orbitals with the following quantum numbers.
n = 3, l = 2
Write condensed orbital notation of electronic configuration of the following element:
Carbon (Z = 6)
Write condensed orbital notation of electronic configuration of the following element:
Chlorine (Z = 17)
Explain in brief, the significance of the azimuthal quantum number.
Indicate the number of unpaired electron in:
Cr (Z = 24)
The principal quantum number (n) and magnetic quantum number (ml) for the valence electrons of rubidium atom (Z = 37) are ____________ respectively.
Which mineral among the following contains vanadium in it?
The three electrons have the following set of quantum numbers:
X = 6, 1, −1, `+1/2`
Y = 6, 0, 0, `+1/2`
Z = 5, 1, 0, `+1/2`
Identify the CORRECT statement.
Which of the following has a greater number of electrons than neutrons?
(Mass number of Mg, C, O and Na is 24, 12, 16 and 23 respectively).
Which one of the following is NOT possible?
The probability density plots of 1s and 2s orbitals are given in Figure:
The density of dots in a region represents the probability density of finding electrons in the region.
On the basis of above diagram which of the following statements is incorrect?
The number of radial nodes for 3p orbital is ______.
Number of angular nodes for 4d orbital is ______.
Orbital angular momentum depends on ______.
Which of the following statements concerning the quantum numbers are correct?
(i) Angular quantum number determines the three dimensional shape of the orbital.
(ii) The principal quantum number determines the orientation and energy of the orbital.
(iii) Magnetic quantum number determines the size of the orbital.
(iv) Spin quantum number of an electron determines the orientation of the spin of electron relative to the chosen axis.
The arrangement of orbitals on the basis of energy is based upon their (n + l) value. Lower the value of (n + l), lower is the energy. For orbitals having same values of (n + l), the orbital with lower value of n will have lower energy.
Based upon the above information, arrange the following orbitals in the increasing order of energy.
1s, 2s, 3s, 2p
The arrangement of orbitals on the basis of energy is based upon their (n + l) value. Lower the value of (n + l), lower is the energy. For orbitals having same values of (n + l), the orbital with lower value of n will have lower energy.
Based upon the above information, arrange the following orbitals in the increasing order of energy.
4s, 3s, 3p, 4d
The arrangement of orbitals on the basis of energy is based upon their (n + l) value. Lower the value of (n + l), lower is the energy. For orbitals having same values of (n + l), the orbital with lower value of n will have lower energy.
Based upon the above information, arrange the following orbitals in the increasing order of energy.
5p, 4d, 5d, 4f, 6s
The arrangement of orbitals on the basis of energy is based upon their (n + l) value. Lower the value of (n + l), lower is the energy. For orbitals having same values of (n + l), the orbital with lower value of n will have lower energy.
Based upon the above information, arrange the following orbitals in the increasing order of energy.
5f, 6d, 7s, 7p
What is the difference between the terms orbit and orbital?
Match the following
| (i) Photon | (a) Value is 4 for N shell |
| (ii) Electron | (b) Probability density |
| (iii) ψ2 | (c) Always positive value |
| (iv) Principal quantum number n | (d) Exhibits both momentum and wavelength |
Match species given in Column I with the electronic configuration given in Column II.
| Column I | Column II |
| (i) \[\ce{Cr}\] | (a) [Ar]3d84s0 |
| (ii) \[\ce{Fe^{2+}}\] | (b) [Ar]3d104s1 |
| (iii) \[\ce{Ni^{2+}}\] | (c) [Ar]3d64s0 |
| (iv) \[\ce{Cu}\] | (d) [Ar] 3d54s1 |
| (e) [Ar]3d64s2 |
Which of the following is the correct plot for the probability density ψ2 (r) as a function of distance 'r' of the electron from the nucleus for 2s orbitals?
