Question # 1

The valence orbital configuration of an element with atomic number 23 is

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3d⁵

3d³, 4s²

3d³, 4s¹, 4p¹

3d²,4s²,4p¹

The credit of discovering neutron goes to

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Rutherford

Langmuir

Chadwick

Austen

Proton was discovered by:

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Chadwick

J.J. Rhomson

Millikan.

Goldstein.

Which of the atoms has 1s², 2s², 2p_x²2p¹_y2p¹_zconfiguration

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Nitrogen

Carbon

Fluorine

Oxygen

Smallest charge of electricity that has been measured so far is

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Charge on a-rays

Charge on electron (1.602 x 10^-19C)

Charge on x-rays

Charge on gamma rays

Neutron was discovered by:

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Chadwick.

Bohr.

Rutherford.

Plank.

The maximum number of electrons in a subshell for which l = 3 is

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14

10

8

4

Electrons arranged in orbitals according to the increasing order of their n + l values, this rule is named as

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Hund's rule

Heisenberg's principle

Paulit exclusion principle

Auf bau principle

Which of the following is not a sub-atomic particle

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Electron

Proton

Neutron

Deuteron

The four quantum numbers of the valency electron of potassium are

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4,1,1,1/2

4,0,0,1/2

4,1,0,1/2

4,4,0,1/2

The energy of the first electron is helium will be

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-13.6 eV

-54.4 eV

-5.44 eV

zero

The limiting line of Blamer series in hydrogen spectrum lies in

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Visible regions

Ultraviolet region

Infrared region

x-rays region

For a 3P subshell the set of principle and azimuthal quantum number is

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n = 1 , l = 2

n = 3, l = 0

n = 3, l = 1

n = 1, l = 3

If the radius of first Bohr orbit be a_o, then the radius of third Bohr orbit would be

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3 x a_o

6 x a_o

9 x a_o

1/2 x a_o

When cathode rays strike the anode metal X-rays are emitted and not the positive rays because

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Cathode rays are material particles

Cathode rays knock out electrons from anode, which emit X-rays when outer electron take their place

Cathode rays are absorbed by the nucleus

Cathode rays become heated

The rules which describe the distribution of electron in atomic energy levels are Auf-ban principle, Pauli's exclusion principle. Hunds rule. The pauli exclusion principle refers to the

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Orientation of orbital in space

Fact that two electrons in the same orbital should have opposite spins

Energy of the orbital

Spin of the electron

The ratio of the ionization energy of H and Be³⁺is

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1 : 1

1 : 3

1 : 9

1 : 16

The radius of first orbit of H-atom is

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4.75 A°

3.84 A°

8.4 A°

0.529 A°

When electron jumps from n₂= 2,3,4,5,.... orbit to n₁= 1 orbit in the hydrogen atom, the radiations emitted give the spectral lines

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Lyman series

Blamer series

Paschen series

Brackett series

Heaviest particle is

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Meson

Neutron

Proton

Electron

Maximum potential energy that an electron can have within the atom is:

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Equal to zero.

Less than zero.

Greater than zero.

Infinite

Rutherford's model of atom failed because:

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The atom did o have a nucleus and electrons

It did not account fro the attraction b/w protons and neutrons

It did no account for the stability of the atom.

There is actually no space b/w the nucleus ad the electrons.

The radius of first orbit of hydrogen atom

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0.329 A°

0.429 A°

0.529 A°

0.229 A°

When the electron jumps form third, fourth, fifth orbits to the second orbit, the transitions are known as

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Paschen

Pfund

Balmer

Brackett

The electronic configuration of an atom/ion can be defined by the following

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Aufbau principle

Pauli's exclusion principle

Hund's Rule

All the above

The orbital in Rutherford's model is

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Spiral

Circular

Both

None

Rutherford's planetary like picture of the atomic modal was defective because

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It did not describe the quantity of positive charge

It did not explain the repulsion of protons within the nucleus

No empty space between nucleus and the electrons

Moving electron should radiate energy

The experimental evidences for the existence of atomic nucleus comes from:

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Line spectrum of hydrogen.

Magnetic bonding of cathode rays.

Millikan oil drop experiment.

Scattering of alpha particles by thin metal foil.

Which of the following is not isoelectronic?

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Na⁺

Mg²⁺

O^2-

Cl^-

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Plank's equations

de Broglie's equations

Heisenburg's equation

None

Anode is the surface on which probability of finding electron is:

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50%

Less than 10%.

More than 95%.

Zero.

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