laboursonline – MCQs, Mock Tests | Chemistry Chemistry MCQ Question

All of the following were theorized by Bohr in his description of the atom except

1. Angular momentum of electrons in multiples of h/2?
2. Electrons revolve in discrete circular orbits
3. Energy of each electron is directly proportional to n2
4. Electrons radiate energy continuously in a given orbit.

✅ Correct Answer: 4

The letters s p d and f are used to represent which quantum numbers

1. Principal
2. Azimuthal
3. Magnetic
4. Spin

✅ Correct Answer: 2

The magnetic quantum number (QN) has its values determined directly by the value of

1. Principal (QN)
2. Azimuthal (QN)
3. Spin (QN)
4. Both a & b

✅ Correct Answer: 2

The atomic number of an element having maximum number of unpaired electrons in p-subshell is

1. 7
2. 10
3. 12
4. 16

✅ Correct Answer: 1

The maximum number of electron in a sub shell with ? = 3fs

1. 6
2. 10
3. 14
4. 18

✅ Correct Answer: 3

Radius of the third shell of H-atom is

1. 5.761 A?
2. 4.761 A?
3. 6.671 A?
4. 3.716 A?

✅ Correct Answer: 2

When an atom absorbs energy the lines in the spectrum will appear which are

1. Brighter
2. Darker
3. Colourless
4. Hard to locate

✅ Correct Answer: 2

Colour of fluorescene produced by cathode rays depends upon

1. Temperature
2. Pressure
3. Volume
4. Composition of glass

✅ Correct Answer: 4

Which one is not true about cathode rays?

1. 9.11x10-31 Kg
2. Cast shadow
3. Heat up the platinum foil
4. Cannot ionize

✅ Correct Answer: 4

Positive rays are produced

1. By burning of gas
2. By cooling of the gas
3. By the bombardment of cathode rays on gas molecules
4. From anode like cathode rays produced from cathode

✅ Correct Answer: 3

A fast moving neutron can eject from nitrogen

1. ? = rays
2. ? = rays
3. ? = rays
4. electrons

✅ Correct Answer: 2

Rutherfords planet like structure was defective and unsatisfactory because

1. Moving e- accelerate towards the nucleus
2. Continuous spectrum
3. behavior of electron remain unexplained
4. all

✅ Correct Answer: 4

The relationship between energy of a photon of light and its frequency is given by

1. de-Broglie duel nature of matter
2. Bohrs model
3. Plancks Quantum theory
4. Rutherfords atomic model

✅ Correct Answer: 3

Splitting of spectral lines when atom is subjected to magnetic field is called

1. Zeemans effect
2. Starks effect
3. Photo electric effect
4. Compton effect

✅ Correct Answer: 1

The velocity of the photon

1. Is independent of wavelength
2. Depends upon source
3. Depends upon its frequency
4. Equals to the square of amplitude

✅ Correct Answer: 1

Which one of the following explain the shape of orbitals

1. Principal of quantum number
2. Azimuthal quantum number
3. Magnetic quantum number
4. Spin quantum number

✅ Correct Answer: 2

Atom cannot be divided into simple unitstheorized by

1. Rutherford
2. Dalton
3. Bohr
4. Schrodinger

✅ Correct Answer: 2

Pressure in gas discharge tube was kept

1. 10 torr
2. 1 torr
3. 0.1 torr
4. 0.01 torr

✅ Correct Answer: 4

The number of fundamental particles in an atom of the lightest isotope carbon are

1. 6
2. 12
3. 18
4. 20

✅ Correct Answer: 3

Angle of deflection was studied by

1. Hitorff
2. Stoney
3. William Crookes
4. J.Perrin

✅ Correct Answer: 4

Increase in atomic number is observed during

1. Alpha emission
2. Beta emission
3. Both a & b
4. Radioactivity

✅ Correct Answer: 2

Positive rays give flash on

1. AgNO3 plate
2. AgCl plate
3. ZnO
4. ZnS

✅ Correct Answer: 4

Free neutron changes into proton with the emission of

1. Neutrino
2. Electron
3. Both a & b
4. Meson

✅ Correct Answer: 3

The value of e/m ratio of electron is

1. 6.02 x 1023 C/kg
2. 1.7588 x 1020 C/kg
3. 9.1095 x 10-31 C/kg
4. 1.7588 x 1011 C/kg

✅ Correct Answer: 4

Charge of electron was measured by

1. J.J Thomson
2. Millikan
3. Rutherford
4. Perrin

✅ Correct Answer: 2

Rutherford bombarded ______________ particles in discovery of nucleus

1. Gamma-rays
2. Alpha-rays
3. Beta-rays
4. X-rays

✅ Correct Answer: 2

Planks theory says energy is emitted

1. In continuous manner
2. Discontinuous manner
3. Simultaneously
4. In the form of heat

✅ Correct Answer: 2

Angular momentum of an electron

1. n2h/2?
2. nk2/2?
3. nh/4?
4. nh/2?

✅ Correct Answer: 4

2nd orbit is _______ away from nucleus of H-atom as compared to 1st orbit is

1. 2-times
2. 3-times
3. 4-times
4. 6 times

✅ Correct Answer: 3

The maximum number of orbitals present in a subshell that is represented by Azimuthal quantum number = 3 will be

1. 1
2. 3
3. 5
4. 7

✅ Correct Answer: 4

The correct electronic configuration of Cu is

1. [Ar]4s1
2. [Ar]4s2
3. [Ar]3d104s1
4. [Ar]3d94s2

✅ Correct Answer: 3

Pfund series are produced in the spectrum of hydrogen atom

1. when electrons jump down to 2nd- orbit
2. when electrons jump down to 3rd- orbit
3. when electrons jump down to 4th- orbit
4. when electrons jump down to 5th- orbit

✅ Correct Answer: 4

Atomic orbits having same evergy are called

1. Degenerate orbitals
2. Bonding molecular orbitals
3. Anti bonding molecular orbitals
4. Half filled orbitals

✅ Correct Answer: 1

Sommerfelds modification in Bohrs model is

1. Orbit is cylindrical
2. Orbit is elliptical
3. Orbit is longitudinal
4. Orbit is asymmetrical

✅ Correct Answer: 2

When electrons collide with heavy metals than ______ are produced.

1. Beta-rays
2. Alpha-rays
3. X-rays
4. Gamma-rays

✅ Correct Answer: 3

Plancks equation is

1. E = mc2
2. mvr = nh/2?
3. E = h?
4. ? = h/mv

✅ Correct Answer: 3

Atom with higher atomic number produces X-rays of

1. Shorter wavelength
2. Larger wavelength
3. X-ray not produced
4. All are possible

✅ Correct Answer: 1

Wavelength of electron was verified by

1. Moseley
2. Davisson and Germer
3. Einstein
4. Roentgen

✅ Correct Answer: 2

Space around nucleus where finding probability of electrons is maximum is called

1. Orbital
2. Orbit is elliptical
3. subshell
4. Electron cloud

✅ Correct Answer: 1

Quantum number which tells the energy of electron is

1. n
2. 1
3. m
4. s

✅ Correct Answer: 1

Electronic configuration of K is

1. [Ar]4s2
2. [Ar]4s1
3. [Kr]5s1
4. [He]2s1

✅ Correct Answer: 2

____________ can expel proteons from paraffins

1. Electron
2. Positron
3. Neutron
4. None of above has such capability

✅ Correct Answer: 3

Milikan used __________ in his atomizer

1. Milk
2. Positron
3. Neutron
4. None of above has such capability

✅ Correct Answer: 3

Milikan used __________ in his atomizer

1. Milk
2. Honey
3. Oil
4. Water

✅ Correct Answer: 3

Centrifugal forces are balanced in atom by

1. Attractive forces
2. Repulsive force
3. Electrons
4. Neutrons

✅ Correct Answer: 1

Spectrum is produced due to

1. Different wavelength
2. Different colours
3. Different intensities
4. all have little contribution

✅ Correct Answer: 1

When 6d orbital is complete the entering electron goes into

1. 7f
2. 7s
3. 7p
4. 7d

✅ Correct Answer: 3

When electron jump into orbit 1 then series obtained is

1. Lyman
2. Paschen
3. Pfund
4. Brackett

✅ Correct Answer: 1

Neutrons moving with an energy of 1.2 MeV are called

1. Fast neutrons
2. Slow neutrons
3. Moderate neutrons
4. All are possible

✅ Correct Answer: 1

Splitting of spectral lines when atoms are subjected to strong electric filed is called

1. Zeeman effect
2. Stark effect
3. Photoelectric effect
4. Compton effect

✅ Correct Answer: 2

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