Chemistry Chapter 2 Entry Test MCQs
26. Energy is inversely proportional to:
a. Wavenumber
b. Wavelength
c. Planck’s constant
d. frequency
27. The Heisenberg Principle states that __.
a. It is impossible to determine accurately both the position and momentum of an electron simultaneously.
b. No two electrons in the same atom can have the same set of four quantum numbers.
c. charged atoms (ions) must generate a magnetic field when they are in motion.
d. Two atoms of the same element must have the same number of protons.
28. Rutherford’s a-particles scattering experiment led to the conclusion that:
a. Mass and positive charge of an atom are concentrated in the nucleus
b. Atoms are electrically neutral
c. Neutrons are present in the nucleus
d. Mass and energy are related
29. The proton and neutron are collectively called
a. Positron
b. Deuteron
c. Nucleon
d. Meson
30. Atom consists of only proton and neutron is called
a. Positron
b. Deuteron
c. Nucleon
d. Meson
31. An alpha particle moving with velocity of electron should have the wavelength times smaller than that of electron:
a. 7344
b. 1836
c. 1845
d. 7700
32. The de-Broglie’s wavelength of a particle having momentum 2.2 x 10-24 kgms-1 (Planck’s constant = 6.6 x 10-34 Js)
a. 3Ao
b. 0.5 Ao
c. 3.5Ao
d. 2Ao
33. Of the following, which has the shortest de Broglie wavelength?
a. A nitrogen molecule moving at a velocity of 1200 mph
b. A nitrogen molecule moving at a velocity of 4000 mph.
c. An nitrogen molecule moving at a velocity of 200 mph
d. A nitrogen molecule moving at a velocity of 1100 mph
34. Which one has shortest wavelength when moving with the same velocity
a. Neutron
b. Proton
c. Positron
d. Electron
35. For which of the following Bohr’s theory is not applicable
a. H–
b. H
c. He+1
d. Li+2
36. Which statement is correct
a. The energy of electron decreases as the value of ‘n’ increases
b. Energy of electron in an atom is negative with reference to infinity
c. The different energy levels are equally quantized
d. Bohr’s theory explains the spectrum of multi-electron system
37. If uncertainty in the position of an electron is zero, the uncertainty in the determination of momentum is
a. Zero
b. > h / 4π
c. Infinite
d. < h / 4π
38. The e/m value of H+ ion in comparison to e/m value of electron is
a. 1836 times lesser
b. four times greater
c. four times lesser
d. 1836 times greater
39. The force that allows electrons to move around the nucleus is
a. electrostatic force
b. nuclear force
c. Gravitational force
d. Weak nuclear force
40. According to Bohr’s atomic model, the radius of the orbit is directly proportional to
a. 1/n
b. n2
c. n
d. 1/n2
41. According to Bohr’s atomic model, the angular momentum of orbits is multiple of
a. 2h/𝜋
b. h/2𝜋
c. 𝜋/2h
d. 2𝜋/h
42. Angular momentum of 2nd orbit of Hydrogen is:
a. h/𝜋
b. h/2𝜋
c. 𝜋/2h
d. 2𝜋/h
43. Radius of the hydrogen atom on going to the first excited state is _ of Bohr’s radius.
a. half
b. Double
c. Same
d. 4 times
44. Rutherford’s experiment on scattering of particles showed for the first time that the atom has
a. Nucleus
b. Electron
c. Neutron
d. Proton
45. Who modified Bohr’s theory by introducing elliptical orbits for electron path
a. Sommerfeld
b. Hund’s
c. Einstein
d. Heisenberg
46. An electron makes a transition from energy state E3 to E1 will emit a photon of frequency
a. ν = (E3 – E1)/h
b. ν = E1 – E3/h
c. ν = (E3 – E1) h
d. None of these
47. All of the following were theorized by Bohr in the description of atom except
a. Electron continuously radiate energy in the form of radiation in a given orbit
b. Angular momentum of electron is multiple of h/2π
c. Distance between successive orbits are increasing
d. Electrons circulate in discrete circular orbit
48. The maximum probability of finding an electron in a hydrogen atom according to Schrodinger is
a. 0.073nm
b. 0.053nm
c. 0.057nm
d. 0.043nm
49. Which one of the following statements is not correct?
a. The angular momentum of the electron in the ground state of hydrogen atom is equal to h/2pi
b. Unit of frequency is cycle per second
c. The radius of first Bohr orbit of hydrogen atom is 2.116 × 10– 8cm
d. Lyman series of hydrogen spectrum occurs in the ultraviolet region
50. In the emission spectrum of hydrogen, which series of emission lines fall in the visible region?
a. Paschen
b. Lyman
c. Pfund
d. Balmer