Structure of Atom

A bulb is rated at 150 watt, converting 8% energy into light. If energy of one photon is 4.42 × 10-19 J, how many photons are emitted by the bulb per second?

1. 27.2 × 1019
2. 4.06 × 1019
3. 1.35 × 1019
4. 2.71 × 1019

Consider the following schematic plots of orbital wavefunction ( r) against distance (r) from the nucleus. [figure] The figure representing two radial nodes in the orbital is

1. D
2. A
3. B
4. C

The ratio of the wavelengths of the light absorbed by a Hydrogen atom when it undergoes n = 2 n = 3 and n = 4 n = 6 transitions, respectively, is

1. 19
2. 14
3. 136
4. 116

Energy and radius of first Bohr orbit of He+ and Li2+ are [Given RH = 2.18 10-18 J, a0 = 52.9 pm]

1. En (Li2+ ) = -19.62 10-16 J; rn (Li2+ ) = 17.6 pm En (He+ ) = -8.72 10-16 J; rn (He+ ) = 26.4 pm
2. En (Li2+ ) = -8.72 10-16 J; rn (Li2+ ) = 17.6 pm En (He+ ) = -19.62 10-16 J; rn (He+ ) = 17.6 pm
3. En (Li2+ ) = -19.62 10-18 J; rn (Li2+ ) = 17.6 pm En (He+ ) = -8.72 10-18 J; rn (He+ ) = 26.4 pm
4. En (Li2+ ) = -8.72 10-18 J; rn (Li2+ ) = 26.4 pm En (He+ ) = -19.62 10-18 J; rn (He+ ) = 17.6 pm

The energy of an electron in the ground state (n = 1) for He+ ion is -x J, then that for an electron in (n = 2) state for Be3+ ion in J is

1. -x
2. - x9
3. -4x
4. - 49x

The quantum numbers of four electrons are given below : I. n = 4; l = 2; ml = -2; s = - 12 II. n = 3; l = 2; ml = 1; s = + 12 III. n = 4; l = 1; ml = 0; s = + 12 IV. n = 3; l = 1; ml = -1; s = + 12 The correct decreasing order of energy of these electrons is

1. IV > II > III > I
2. I > III > II > IV
3. III > I > II > IV
4. I > II > III > IV

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

Select the correct Statements from the following : Choose the correct answer from the options given below.

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

The relation between nm (nm = the number of permissible values of magnetic quantum number (m)) for a given value of azimuthal quantum number (l), is

1. l = 2nm + 1
2. nm = 2l2 + 1
3. nm = l + 2
4. l = nm - 12

Identify the incorrect statement from the following.

1. All the five 5d orbitals are different in size when compared to the respective 4d orbitals.
2. All the five 4d orbitals have shapes similar to the respective 3d orbitals.
3. In an atom, all the five 3d orbitals are equal in energy in free state.
4. The shapes of dxy, dyz and dzx orbitals are similar to each other; and dx2-y2 and dz2 are similar to each other.

If radius of second Bohr orbit of the He+ ion is 105.8 pm, what is the radius of third Bohr orbit of Li2+ ion?

1. 158.7 pm
2. 15.87 pm
3. 1.587 pm
4. 158.7 A

When electromagnetic radiation of wavelength 300 nm falls on the surface of a metal, electrons are emitted with the kinetic energy of 1.68 105 J mol-1. What is the minimum energy needed to remove an electron from the metal? (h = 6.626 10-34 J s, c = 3 108 m s-1, NA = 6.022 1023 mol-1)

1. 2.31 105 J mol-1
2. 2.31 106 J mol-1
3. 3.84 104 J mol-1
4. 3.84 10-19 J mol-1

A particular station of All India Radio, New Delhi broadcasts on a frequency of 1,368 kHz (kilohertz). The wavelength of the electromagnetic radiation emitted by the transmitter is : [speed of light c = 3.0 108 m s-1]

1. 21.92 cm
2. 219.3 m
3. 219.2 m
4. 2192 m

From the following pairs of ions which one is not an iso-electronic pair?

1. Fe2+, Mn2+
2. O2-, F-
3. Na+, Mg2+
4. Mn2+, Fe3+

The number of protons, neutrons and electrons in 175 71Lu, respectively, are :

1. 104, 71 and 71
2. 71, 71 and 104
3. 175, 104 and 71
4. 71, 104 and 71

4d, 5p, 5f and 6p orbitals are arranged in the order of decreasing energy. The correct option is :

1. 6p > 5f > 4d > 5p
2. 5f > 6p > 4d > 5p
3. 5f > 6p > 5p > 4d
4. 6p > 5f > 5p > 4d

Which of the following series of transitions in the spectrum of hydrogen atom falls in visible region?

1. Paschen series
2. Brackett series
3. Lyman series
4. Balmer series

Which one is a wrong statement?

1. Total orbital angular momentum of electron in s-orbital is equal to zero.
2. An orbital is designated by three quantum numbers while an electron in an atom is designated by four quantum numbers
3. The electronic configuration of N atom is [figure]
4. The value of m for dz2 is zero.

Which one is the wrong statement ?

1. The uncertainty principle is E t h4
2. Half filled and fully filled orbitals have greater stability due to greater exchange energy, greater symmetry and more balanced arrangement.
3. The energy of 2s-orbital is less than the energy of 2p-orbital in case of hydrogen like atoms.
4. de-Broglie's wavelength is given by = hmv, where m = mass of the particle, v = group velocity of the particle.

Two electrons occupying the same orbital are distinguished by

1. azimuthal quantum number
2. spin quantum number
3. principal quantum number
4. magnetic quantum number

How many electrons can fit in the orbital for which n = 3 and l = 1?

1. 2
2. 6
3. 10
4. 14

Which of the following pairs of d-orbitals will have electron density along the axes ?

1. dz2, dxz
2. dxz, dyz
3. dz2, dx2-y2
4. dxy, dx2-y2

Which is the correct order of increasing energy of the listed orbitals in the atom of titanium ? (At. no. Z = 22)

1. 4s 3s 3p 3d
2. 3s 3p 3d 4s
3. 3s 3p 4s 3d
4. 3s 4s 3p 3d

The number of d-electrons in Fe2+ (Z = 26) is not equal to the number of electrons in which one of the following ?

1. d-electrons in Fe (Z = 26)
2. p-electrons in Ne (Z = 10)
3. s-electrons in Mg (Z = 12)
4. p-electrons in Cl (Z = 17)

The angular momentum of electron in 'd' orbital is equal to

1. 2 3
2. 0
3. 6
4. 2

What is the maximum number of orbitals that can be identified with the following quantum numbers? n = 3, l = 1, ml = 0

1. 1
2. 2
3. 3
4. 4

Calculate the energy in joule corresponding to light of wavelength 45 nm. (Planck's constant, h = 6.63 10-34 J s, speed of light, c = 3 108 m s-1)

1. 6.67 1015
2. 6.67 1011
3. 4.42 10-15
4. 4.42 10-18

Be2+ is isoelectronic with which of the following ions?

1. H+
2. Li+
3. Na+
4. Mg2+

What is the maximum number of electrons that can be associated with the following set of quantum numbers ? n = 3, l = 1 and m = -1

1. 4
2. 2
3. 10
4. 6

Based on equation E = -2.178 10-18 J ( Z2n2 ), certain conclusions are written. Which of them is not correct ?

1. Equation can be used to calculate the change in energy when the electron changes orbit.
2. For n = 1, the electron has a more negative energy than it does for n = 6 which means that the electron is more loosely bound in the smallest allowed orbit.
3. The negative sign in equation simply means that the energy of electron bound to the nucleus is lower than it would be if the electrons were at the infinite distance from the nucleus.
4. Larger the value of n, the larger is the orbit radius.