# How many unpaired electrons are present in Ni2+ cation (atomic number = 28) 1. 0 2. 2 3. 4 4. 6

Subtopic:  AUFBAU Principle |
64%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

Number of unpaired electrons in 1s2 2s2 2p3 is -

1. 2

2. 0

3. 3

4. 1

Subtopic:  Pauli's Exclusion Principle & Hund's Rule |
86%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

The quantum numbers of four electrons are given below.

n            $\mathcal{l}$           m          s

(1) Electron 1             3            0             0           -1/2

(2) Electron 2             4            0             0           1/2

(3) Electron 3            3             2             0           1/2

(4) Electron 4            3             1             0           -1/2

The correct order of decreasing energy of these electrons is -

1. Electron 3 > Electron 1 > Electron 4> Electron 2

2. Electron 4> Electron 2 > Electron 3 > Electron 1

3. Electron 3 > Electron 2 > Electron 4 > Electron 1

4. Electron 2 > Electron 4 > Electron 3 > Electron 1

Subtopic:  Quantum Numbers & Schrodinger Wave Equation |
70%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

Which type of radiation is not emitted by the electronic structure of atoms:

1. Ultraviolet light

2. X-rays

3. Visible light

4. y-rays

64%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

An absorption line of the lowest frequency in the transition of hydrogen spectra is:

1. n=1 to n=2

2. n=3 to n=8

3. n=2 to n=1

4. n=8 to n=3

Subtopic:  Hydrogen Spectra |
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

If uncertainty in the position of an electron is zero the uncertainty in its momentum will be:

1. <h/4$\mathrm{\pi }$

2. >h/4$\mathrm{\pi }$

3. zero

4. infinite

Subtopic:  Heisenberg Uncertainty Principle |
51%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

The maximum number of atomic orbitals associated with a principal quantum number 5 is-

1. 9

2. 12

3. 16

4. 25

Subtopic:  Quantum Numbers & Schrodinger Wave Equation | Shell & Subshell |
70%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

The de Broglie wavelength of electron of He+ ion is 3.329Å. If the photon emitted upon de-excitation of this He+ ion is made to hit H atom in its ground state so as to liberate electron from it, what will be the de Broglie's wavelength of photoelectron ?

1. 0.1518 Å

2. 6.1518 Å

3. 2.3518 Å

4. 4.1218 Å

Subtopic:  De Broglie Equation |
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

Velocity of helium atom at 300 K is 2.40 x 102 meter per sec. What is its wavelength? (mass number of helium is 4) -

1. 0.416 nm

2. 0.83 nm

3. 803 Å

4. 8000 Å

From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch

The de-Broglie wavelength of a particle having the momentum of
3.3 x 10-24 kg m s-1 will be;

1. 0.002 Å

2. 0.02 Å

3. 0.2 Å

4. 2Å

Subtopic:  Planck's Theory |
77%
From NCERT
To view explanation, please take trial in the course.
NEET 2025 - Target Batch
Hints
To view explanation, please take trial in the course.
NEET 2025 - Target Batch