Structure of Atom

Which one of the following about an electron occupying the 1s orbital in a hydrogen atom is incorrect? (Bohr's radius is represented by a0)

1. The probability density of finding the electron is maximum at the nucleus
2. The total energy of the electron is maximum when it is at a distance a0 from the nucleus
3. The electron can be found at a distance 2a0 from the nucleus
4. The 1s orbital is spherically symmetrical

Consider the ground state of chromium atom (Z = 24). How many electrons are with Azimuthal quantum number l = 1 and l = 2 respectively ?

1. 16 and 5
2. 12 and 5
3. 12 and 4
4. 16 and 4

Which of the following postulate of Bohr's model of hydrogen atom is not in agreement with quantum mechanical model of an atom?

1. The electron in a H atom's stationary state moves in a circle around the nucleus.
2. An atom can take only certain distinct energies E1, E2, E3, etc. These allowed states of constant energy are called the stationary states of atom.
3. An atom in a stationary state does not emit electromagnetic radiation as long as it stays in the same state.
4. When an electron makes a transition from a higher energy stationary state to a lower energy stationary state, then it emits a photon of light.

For electrons in '2s' and '2p' orbitals, the orbital angular momentum values, respectively are:

1. 0 and 6 h2
2. 0 and 2 h2
3. 2 h2 and 0
4. h2 and 2 h2

According to Bohr's model of hydrogen atom, which of the following statement is incorrect?

1. Radius of 4th orbit is four times larger than that of 2nd orbit
2. Radius of 8th orbit is four times larger than that of 4th orbit
3. Radius of 6th orbit is three times larger than that of 4th orbit
4. Radius of 3rd orbit is nine times larger than that of 1st orbit

Which of the following statements are true? Choose the correct answer from the options given below:

1. (A) and (B) only
2. (B) and (D) only
3. (C) and (D) only
4. (A), (B) and (C) only

If a0 is denoted as the Bohr radius of hydrogen atom, then what is the de Broglie wavelength (λ) of the electron present in the second orbit of hydrogen atom? [n : any integer]

1. 8 a0n
2. 2a0n
3. na04
4. 4 a0n

For hydrogen like species, which of the following graphs provides the most appropriate representation of E vs Z plot for a constant n? [E : Energy of the stationary state, Z : atomic number, n = principal quantum number]

1. [figure]
2. [figure]
3. [figure]
4. [figure]

Given below are two statements : In the light of the above statements, choose the correct answer from the options given below :

1. Statement I is false but Statement II is true
2. Both Statement I and Statement II are true
3. Both Statement I and Statement II are false
4. Statement I is true but Statement II is false

In a multielectron atom, which of the following orbitals described by three quantum numbers will have same energy in absence of electric and magnetic fields? Choose the correct answer from the options given below:

1. B and C Only
2. C and D Only
3. A and B Only
4. D and E Only

Which of the following is/are not correct with respect to energy of atomic orbitals of hydrogen atom? Choose the correct answer from the options given below :

1. (A) and (B) only
2. (A) and (C) only
3. (B) and (D) only
4. (C) and (D) only

For hydrogen atom, the orbital/s with lowest energy is/are : Choose the correct answer from the options given below :

1. A only
2. B only
3. B, C and D only
4. A and E only

Heat treatment of muscular pain involves radiation of wavelength of about 900 nm. Which spectral line of H atom is suitable for this? Given : Rydberg constant RH = 105 cm-1, h = 6.6 10-34 J s, c = 3 108 m/s

1. Lyman series, 1
2. Balmer series, 2
3. Paschen series, 5 3
4. Paschen series, 3

Given below are two statements : In the light of the above statements, choose the correct answer from the options given below :

1. Both Statement I and Statement II are true
2. Both Statement I and Statement II are false
3. Statement I is false but Statement II is true
4. Statement I is true but Statement II is false

Given below are two statements about X-ray spectra of elements : In the light of the above statements, choose the correct answer from the options given below :

1. Statement I is false but Statement II is true
2. Both Statement I and Statement II are true
3. Statement I is true but Statement II is false
4. Both Statement I and Statement II are false

Radius of the first excited state of Helium ion is given as : a0 radius of first stationary state of hydrogen atom.

1. r = a04
2. r = 2a0
3. r = 4a0
4. r = a02

Given below are two statements : In the light of the above statements, choose the correct answer from the options given below :

1. Statement I is false but Statement II is true
2. Both Statement I and Statement II are false
3. Statement I is true but Statement II is false
4. Both Statement I and Statement II are true

Niobium (Nb) and ruthenium (Ru) have “x” and “y” number of electrons in their respective 4 d orbitals. The value of x+y is .

Compare the energies of following sets of quantum numbers for multielectron system. (A) n = 4, l = 1 (B) n = 4, l = 2 (C) n = 3, l = 1 (D) n = 3, l = 2 (E) n = 4, l = 0 Choose the correct answer from the options given below :

1. (E) > (C) > (A) > (D) > (B)
2. (B) > (A) > (C) > (E) > (D)
3. (C) < (E) < (D) < (A) < (B)
4. (E) < (C) < (D) < (A) < (B)

Match List I with List II Choose the correct answer from the options given below:

1. A-IV, B-III, C-II, D-I
2. A-I, B-IV, C-III, D-II
3. A-III, B-II, C-I, D-IV
4. A-II, B-I, C-IV, D-III

Based on Heisenberg's uncertainty principle, the uncertainty in the velocity of the electron to be found within an atomic nucleus of diameter 10-15 m is 109 ms-1 (nearest integer) [Given : mass of electron = 9.1 10-31 kg, Planck's constant (h) = 6.626 10-34 Js] (Value of = 3.14)

A hypothetical electromagnetic wave is shown below. [figure] The frequency of the wave is x 1019 Hz. x = (nearest integer)

Wavenumber for a radiation having 5800 Å wavelength is x 10 cm-1. The value of x is . (Integer answer)

Frequency of the de-Broglie wave of electron in Bohr's first orbit of hydrogen atom is 1013 Hz (nearest integer). [Given : RH (Rydberg constant) = 2.18 10-18 J, h (Planck's constant) = 6.6 10-34 J. s.]

For hydrogen atom, energy of an electron in first excited state is -3.4 eV. K.E. of the same electron of hydrogen atom is x eV. Value of x is 10-1 eV. (Nearest integer)

The value of Rydberg constant (RH) is 2.18 10-18 J. The velocity of electron having mass 9.1 10-31 kg in Bohr's first orbit of hydrogen atom = 105 ms-1 (nearest integer).

In an atom, total number of electrons having quantum numbers n = 4, |ml| = 1 and ms = - 12 is .

The de-Broglie's wavelength of an electron in the 4th orbit is 0. (a0 = Bohr's radius)

The maximum number of orbitals which can be identified with n = 4 and ml = 0 is .

According to the wave-particle duality of matter by de-Broglie, which of the following graph plot presents most appropriate relationship between wavelength of electron ( ) and momentum of electron (p)?

1. [figure]
2. [figure]
3. [figure]
4. [figure]