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प्रश्न
Write a note on ‘Principal Quantum number.
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उत्तर
Principal quantum number (n):
- Principal quantum number indicates the principal shell or main energy level to which the electron belongs.
- It is denoted by ‘n’ and is a positive integer with values 1, 2, 3, 4, 5, 6, ….
- A set of atomic orbitals with a given value of ‘n’ constitutes a single shell. These shells are also represented by the letters K, L, M, N, etc.
- With an increase of ‘n’, the number of allowed orbitals in that shell increases and is given by n2.
- The allowed orbitals in the first four shells are given below:
Principal quantum number (n) Shell symbol Allowed number of orbitals (n2) Size of shell 1 K 1 ↓ increases 2 L 4 3 M 9 4 N 16 - As the value of ‘n’ increases, the distance of the shell from the nucleus increases, and the size of the shell increases. Its energy also goes on increasing.
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संबंधित प्रश्न
Using s, p, d notations, describe the orbital with the following quantum numbers n = 1, l = 0.
Using s, p, d notations, describe the orbital with the following quantum numbers n = 3; l =1.
Using s, p, d notations, describe the orbital with the following quantum numbers n = 4; l = 2.
Using s, p, d notations, describe the orbital with the following quantum numbers n = 4; l =3.
Give the names of quantum numbers.
Define the term Electronic configuration.
State and explain Pauli’s exclusion principle.
State the order of filling atomic orbitals following Aufbau principle.
Explain the anomalous behaviour of chromium.
Write orbital notations for the electron in orbitals with the following quantum numbers.
n = 2, l = 1
Write condensed orbital notation of electronic configuration of the following element:
Lithium (Z = 3)
Indicate the number of unpaired electrons in \[\ce{Si}\] (Z = 14).
Indicate the number of unpaired electron in:
Cr (Z = 24)
Which mineral among the following contains vanadium in it?
The designation of a subshell with n = 6 and l = 2 is ____________.
Which one of the following orders is CORRECT in case of energy of the given subshells?
P: n = 4; l = 3
Q: n = 5; I = 1
R: n = 5; l = 0
S: n = 4; l = 2
How many electrons in 19K have n = 3, l = 1?
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).
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?
Total number of orbitals associated with third shell will be ______.
Orbital angular momentum depends on ______.
Which of the following sets of quantum numbers are correct?
| `n` | `l` | `m_l` | |
| (i) | 1 | 1 | +2 |
| (ii) | 2 | 1 | +1 |
| (iii) | 3 | 2 | –2 |
| (iv) | 3 | 4 | –2 |
Which of the following orbitals are degenerate?
3dxy, 4dxy 3dz2, 3dyz, 4dyz, 4dz2
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?
