Structure of atom practice · Mixed difficulty

If ${r_1}$ is the radius of the first orbit, the radius of ${n^{th}}$ orbit of H-atom is given by

When an electron of charge e and mass m moves with velocity u about the nuclear charge Ze in the circular orbit of radius r, the potential energy of the electron is given by:

Time period of a wave is $5 \times {10^{ - 3}}s$, what is the frequency?

Which of the following transition of electron in the Hydrogen atom will emit maximum energy

Given below are two statements.
Statement I According to Bohr’s model of an atom, qualitatively the magnitude of velocity of electron increases with decrease in positive charges on the nucleus as there is no strong hold on the electron by the nucleus.
Statement II According to Bohr’s model of an atom, qualitatively the magnitude of velocity of electron increases with decrease in principal quantum number.
In the light of the above statements, choose the most appropriate answer from the options given below.

The measurement of the electron position is associated with an uncertainty in momentum, which is equal to $1 \times {10^{ - 18}}\;\mathrm{g\;cm\;}{\mathrm{s}^{ - 1}}.$. The uncertainty in electron velocity is: (mass of an electron is$9 \times {10^{ - 28}}\;\mathrm{g}$)

Assertion: All p-orbitals have only one planar node.

Reason: The number of radial nodes depends on the principal quantum number only.

The number of electrons with the azimuthal quantum number $l = 1$ and 2 for ${\mathrm{\;}_{24}}\mathrm{Cr}$ in ground state are:

A patient is asked to drink $\mathrm{BaS}{\mathrm{O}_4}$ solution for examining the stomach by X-rays, because X-rays are:

The threshold energy is given as ${E_0}$ and radiation of energy $E$ falls on metal, then K.E is given as

Which of the following has maximum energy

The orbital cylindrically symmetrical about x-axis is:

Which statement relating to the spectrum of H atom is false?

Which of the following pair is not isoelectronic species?
$(At. no. Sm, 62; Er, 68; Yb, 70; Lu, 71; Eu, 63; Tb, 65 ; \mathrm{Tm}, 69)$

Consider the element $Mg,\,\,\,AI,\,\,\,S,\,\,P$ and $Si,$ the correct increasing order of their first ionisation enthalpy is

The number of radial nodes of 3s and 2p-orbitals are respectively

If there are five radial nodes, when what can be the correct representation of the orbital for $n = 8$

The number of elliptical orbits, including circular orbits in the M-shell of an atom is:

The ratio between the neutrons present in carbon and silicon with respect to atomic masses of 12 and 28 is:

Which of the following transitions of electrons in the H-atom will emit maximum energy

If an electron has spin quantum number of $+ \frac{1}{2}$ and a magnetic quantum number of -1, it cannot be represented in an

The number of protons, neutrons and electrons in ${}_{71}^{175}\mathrm{Lu}$ , respectively, are

The frequency of radiation emitted when the electron falls from n=4 to n=1 in a hydrogen atom will be (Given, ionisation energy of $103\,H = 2.18 \times {10^{ - 18}}\mathrm{\;J\;ato}{\mathrm{m}^{ - 1}}\mathrm{\;and\;}h = 6.625 \times {10^{ - 34}}\mathrm{\;Js}$

The incorrect statement about Bohr’s orbit of hydrogen atom is

The amount of energy required to remove the electron from a $\mathrm{L}{\mathrm{i}^{2 + }}$ ion in its ground state is how many times greater than the amount of energy required to remove the electron from an H atom in its ground state?

What is the work function of the metal, if the light of wavelength $4000\,\mathop {\,\mathrm{A}}\limits^\mathrm{o}$ generates photoelectron of velocity $6 \times {10^5}m{s^{ - 1}}$ from it? (Mass of electron $= 9 \times {10^{31}}\,kg,$ Velocity of light $= 3 \times {10^8}\,m{s^{ - 1}},$ Planck’s constant $= 6.626 \times {10^{ - 34}}\,Js,$ Charge of electron $= 1.6 \times {10^{ - 19}}\,Je{V^{ - 1}})$

If the following particles travel with equal speed, then for which particle the wavelength will be longest?

Which one is wrong statement?

Assertion :- No two electrons in an atom can have the same values of four quantum numbers.

Reason :- No two electrons in an atom can be simultaneously in the same shell, same subshell
same orbitals and have same spin.

The orbital angular momentum for an electron revolving in an orbit is given by $\sqrt {l\left( {l + 1} \right)} \frac{h}{{2\pi }}$. This momentum for an s-electron will be given by