21213.What is the lowest energy of the spectral line emitted by the hydrogen atom in the Lyman series?
(h = Planck's constant, c = velocity of light, R = Rydberg's constant)
(h = Planck's constant, c = velocity of light, R = Rydberg's constant)
$\dfrac{\text{5hcR}}{\text{36}}$
$\dfrac{\text{4hcR}}{\text{3}}$
$\dfrac{\text{3hcR}}{\text{4}}$
$\dfrac{\text{7hcR}}{\text{144}}$
21214.98Cf246 was formed along with a neutron when an unknown radioactive substance was bombarded with 6C12. The unknown substance was
91Pa234
90Th234
92U235
92U238
21215.The correct set of four quantum numbers for the valence electron of rubidium atom (Z = 37) is
5, 0, 0, + $\dfrac{1}{2}$
5, 1, 0, + $\dfrac{1}{2}$
5, 1, 1, + $\dfrac{1}{2}$
6, 0, 0, + $\dfrac{1}{2}$
21216.Identify the wrong statement in the following:
Atomic radius of the elements increases as one moves down the first group of the periodic table
Atomic radius of the elements decreases as one moves across from left to right in the 2nd period of the periodic table
Amongst isoelectronic species, smaller the positive charge on the cation, smaller is the ionic radius
Amongst isoelectronic species, greater the negative charge on the anion, larger is the ionic radius
21217.A gas absorbs a photon of 355 nm and emits at two wavelengths. If one of the emissions is at 680 nm, the other is at:
518 nm
1035 nm
325 nm
743 nm
21218.During the emission of a positron from a nucleus, the mass number of the daughter element remains the same but the atomic number
is decreased by 1 unit
is decreased by 2 units
is increased by 1 unit
remains unchanged
21219.The wave number of the spectral line in the emission spectrum of hydrogen will equal to $\dfrac{8}{9}$ times the Rydberg's constant if the electron jumps from ______.
n = 10 to n = 1
n = 3 to n = 1
n = 2 to n = 1
n = 9 to n = 1
21220.An electron from one Bohr stationary orbit can go to next higher orbit
by emission of electromagnetic radiation
by absorption of any electromagnetic radiation
by absorption of electromagnetic radiation of particular frequency
without emission or absorption of electromagnetic radiation
21221.The energy required to break one mole of Cl – Cl bonds in Cl2 is 242 kJ mol–1. The longest wavelength of light capable of breaking a single Cl – Cl bond is
(c = 3 × 108 ms–1 and NA = 6.02 × 1023 mol–1)
(c = 3 × 108 ms–1 and NA = 6.02 × 1023 mol–1)
594 nm
640 nm
700 nm
494 nm
21222.Which one of the following sets of ions represents a collection of isoelectronic species?
K+, Cl–, Ca2+, Sc3+
Ba2+, Sr2+, K+, S2–
N3–, O2–, F–, S2–
Li+, Na+, Mg2+, Ca2+
21224.If the 1st ionization energy of H atom is 13.6 eV, then the 2nd ionization energy of He atom is
27.2 eV
40.8 eV
54.4 eV
108.8 eV
21225.The atomic number of an element ‘M’ is 26. How many electrons are present in the M-shell of the element in its M3+ state?
11
15
14
13
21226.The set of quantum numbers for the outermost electron for copper in its ground state is
3, 2, 2, + 1/2
4, 1, 1, + 1/2
4, 2, 2, + 1/2
4, 0, 0, + 1/2
21227.The maximum number of electrons that can have principal quantum number, n = 3, and spin quantum number, ms = $-\dfrac{1}{2}$, is
5
7
9
11
21228.The number of electrons and neutrons of an element is 18 and 20 respectively. Its mass number is
2
37
17
38
21229.Ionisation energy of He+ is 19.6 × 10–18 J atom–1. The energy of the first stationary state (n = 1) of Li2+ is
4.41 × 10–16 J atom–1
–4.41 × 10–17 J atom–1
–2.2 × 10–15 J atom–1
8.82 × 10–17 J atom–1
21230.The de Broglie wavelength of a tennis ball of mass 60 g moving with a velocity of 10 metres per second is approximately (Planck's constant h = 6.63 × 10–34 Js)
10–33 metre
10–31 metre
10–16 metre
10–25 metre
21231.In an atom, an electron is moving with a speed of 600 m/s with an accuracy of 0.005%. Certainity with which the position of the electron can be located is
(h = 6.6 × 10–34 kg m2s–1, mass of electron, em = 9.1 × 10–31 kg)
(h = 6.6 × 10–34 kg m2s–1, mass of electron, em = 9.1 × 10–31 kg)
5.10 × 10–3 m
1.92 × 10–3 m
3.84 × 10–3 m
1.52 × 10–4 m