The mass of one mole of electron is
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Atomic Structure MCQs for NEET — Chemistry Questions with Answers
Practice free Atomic Structure (Chemistry) NEET multiple-choice questions online with instant answers and detailed explanations. No login required.
For the electronic transition from n = 2 to n = 1 which one of the following will produce shortest wave length?
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Explanation
For the transition from n=2 to n=1, the wavelength emitted is inversely proportional to the nuclear charge (Z). The higher the nuclear charge, the shorter the wavelength emitted. Among the given options, Li^(2+) has the highest nuclear charge (Z=3), so it will emit the shortest wavelength for the n=2 to n=1 transition.
The energy required to dislodge electron from excited isolated H atom (IE = 13.6eV) is
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Velocity of electron in the first orbit of H-atom is compared to that of velocity of light is approximately
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Explanation
The velocity of an electron in the first orbit (n=1) of a hydrogen atom is approximately 1/137 times the speed of light. This value is known as the fine-structure constant and arises from the relativistic correction to the Bohr model of the hydrogen atom.
How many electrons in Cu atom have (n + ) = 4
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For a certain particle, it is found that uncertainty 1840 in velocity is reciprocal of uncertainty in position This implies that
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Suggest two transitions in hydrogen spectrum for which wave number ratio is 108:7
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Explanation
The wave number ratio of 108:7 corresponds to the transitions 2 → 1 and 4 → 3 in the hydrogen spectrum. This can be calculated using the Rydberg formula, which relates the wavenumber to the energy levels involved in the transition.
The ratio of K.E. to P.E. of an electron in Bohr orbit of H like species is
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Explanation
$ K.E = { Ze ^ 2 \over 2 r } P.E = { Ze ^2 \over r } \therefore {K.E \over P.E} = { 1/2 \over -1 } = -1.2 $
For particles having same KE., the de-broglie wavelength is
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In one joule of energy, the number of photon with wave number equal to is
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Explanation
$ E = h \nu = nh { c \over \lambda } = nhc \bar v \therefore now E = 1 , \bar v = x \therefore n = { 1 \over hcx } = ( hcx)^{-1} $
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