Atomic Structure

The radius of second orbit of hydrogen atom is same as that of orbit ( $n$ ) of an ion ( $x$ ), $n$ and $x$ are respectively.

An electromagnetic radiation of wavelength 331.5 nm is made to strike the surface of a metal. Electrons are emitted with a kinetic energy of $12 \times 10^5 \mathrm{~J} \mathrm{~mol}^{-1}$. The work function (in eV ) of the metal is $\left(...

Observe the following statements.
Statement -I Rutherford model of an atom cannot explain the stability of an atom.
Statement-II The wavelength of X-rays is higher than the wavelength of microwaves.
The correct answer is

In hydrogen atom, an electron is transferred from an orbit of radius 1.3225 nm to another orbit of radius 0.2116 nm . What is the energy (in J ) of emitted radiation?

In $\mathrm{Sr}(Z=38)$, the number of electrons with $l=0$ is $x$, number of electrons with $l=2$ is $y \cdot(x-y)$ is equal to ( $l=$ Azimuthal quantum number)

The energy associated with electron in first orbit of hydrogen atom is $-2.18 \times 10^{-18} \mathrm{~J}$. The frequency of the light required (in Hz ) to excite the electron to fifth orbit is ( $h=6.6 \times 10^{-34} \mathrm{Js}$ )

In the atomic spectrum of hydrogen, the wavelengths of the spectral lines corresponding to electronic transitions (i) $n=4$ to $n=2$ and (ii) $n=3$ to $n=1$ are $\lambda_1$ and $\lambda_2 \mathop {\rm{A}}\limits^{\rm{o}}$ respectively. The ...

Work functions of four metals $M_1, M_2, M_3$ and $M_4$ are $4.8,4.3,4.75$ and 3.75 eV respectively. The metals which do not show photoelectric effect when light of wavelength 310 nm falls on the metals are

When electromagnetic radiation of wavelength 310 nm falls on the surface of a metal having work function 3.55 eV , the velocity of photoelectrons emitted is $x \times 10^5 \mathrm{~ms}^{-1}$. The value of $x$ is (Nearest integer) $\left(m_e...

The radius of stationary state $(n=2)$ of hydrogen atom is $x \mathrm{pm}$. The radius of stationary state $(n=3)$ of $\mathrm{He}^{+}$ion (in pm) is

The electron in hydrogen atom undergoes transition from higher orbits to an orbit of radius 476.1 pm . This transition corresponds to which of the following series?

Identify the incorrect statement from the following?

Identify the pair of species having same energy from the following. (The number given in the bracket corresponds to principal quantum number ( $n$ ) in which the electron is present.)

Which one of the following corresponds to the wavelength of line spectrum of H atom in its Balmer series ? ( $R=$ Rydberg constant)

The kinetic energy of electrons emitted, when radiation of frequency $1.0 \times 10^{15} \mathrm{~Hz}$ hits a metal, is $2 \times 10^{-19} \mathrm{~J}$. What is the threshold frequency of the metal (in Hz )? $\left(h=6.6 \times 10^{-34} \ma...

If $n, l$ represent the principal and azimuthal quantum numbers respectively, the formula used to know the number of radial nodes possible for a given orbital is

If the radius of first orbit of hydrogen like ion is $1.763 \times 10^{-2} \mathrm{~nm}$, the energy associated with that orbit (in J ) is

The uncertainty in determination of position of a small ball of mass 10 g is $10^{-33} \mathrm{~m}$. With what $\%$ of accuracy its speed can be measured, if it has a speed of 52.5 $\mathrm{ms}^{-1} ?\left(h=6.6 \times 10^{-34} \mathrm{Js}\...

The wavenumber of first spectral line of Lyman series of $\mathrm{He}^{+}$ion is $x \mathrm{~m}^{-1}$. What is the wave number ( $\mathrm{in}^{-1}$ ) of second spectral line of Balmer series of $\mathrm{Li}^{2+}$ ion?

Two statements are given below :Statement I : In H atom, the energy of $2 s$ and $2 p$ orbitals is same.Statements II : In He atom, the energy of $2 s$ and $2 p$ orbitals is same.
The correct answer is

The wavelength of an electron is $10^{3} \mathrm{~nm}$. What is its momentum in $\mathrm{kg} \mathrm{ms}^{-1}$ ? ( $\left.h=6.625 \times 10^{-34} \mathrm{Js}\right)$

The number of electrons with $(n+l)$ values equal to 3,4 and 5 in an element with atomic number $(Z) 24$ are respectively
( $n=$ principal quantum number and $l=$ azimuthal quantum number)

The energy of second orbit of hydrogen atom is $-5.45 \times 10^{-19} \mathrm{~J}$. What is the energy of first orbit of $\mathrm{Li}^{2+}$ ions (in J)?

In the reaction I and II the covalencies of Be and Al in $X$ and $Y$ are respectively
I. $\mathrm{Be}(\mathrm{OH})_2+\underset{\text { (Excess) }}{\mathrm{NaOH}} \longrightarrow X$
II. $\mathrm{Al}(\mathrm{OH})_3+\underset{\text { (Excess) ...

A 100 W bulb emits light of wavelength
$x \mathop {\rm{A}}\limits^{\rm{o}} $. What is the value of $x$, if the number of photons emitted is $2.0 \times 10^{20} \mathrm{~s}^{-1}$ ?
$$ \left(h=6.63 \times 10^{-34} \mathrm{Js}, 1 \mathrm{~W}=1...

The ratio of the difference in energy between the first and second Bohr orbits to that between the second and third orbit is

Identify the impossible quantum number set for the electron from the following.

$\mathrm{Cr}^{2+}$ and $\mathrm{Mn}^{3+}$ do possess $d^4$ electronic configuration. So,

The hybridisations of the central atom in the molecules $\mathrm{BF}_3, \mathrm{BeF}_2, \mathrm{BrF}_3$ are respectively.

The radius of first Bohr orbit of hydrogen atom is same as that of orbit $(n)$ of hydrogen like species $X .(n)$ and $X$ respectively are

When compared with alkaline earth metals, the alkali metals have

The energy of electron in hydrogen atom when present in $n=1, n=2$ and $n=3$ will be in the ratio of

What is the approximate angular momentum (in J s ) of electron in hydrogen atom in its ground state?
\(\left(h=6.625 \times 10^{-34} \mathrm{~J} \mathrm{~s}\right)\)

The threshold frequency of a metal is $10^{15} \mathrm{~s}^{-1}$. The ratio of maximum kinetic energies of the photoelectrons, when the metal is made to strike with radiations of frequencies $1.5 \times 10^{15} \mathrm{~s}^{-1}$ and $2.0 \t...

The radius of third orbit of hydrogen atom is $R \mathrm{pm}$. The radius of second orbit of $\mathrm{He}^{+}$ion (in pm is)

Consider the following.
I. The electron spin quantum number describes the orientation of the spin of the nucleus with respect to the magnetic field.
II. The orbitals represented by the quantum numbers $n=3, l=2, m=+2$ and $n=3, l=2, m=-2$ h...

The wavelength of second line of Balmer series of hydrogen atom is $\lambda \mathrm{nm}$. What is the wavelength of first line of Lyman series of $\mathrm{He}^{+}$ion (in nm )?

The approximate ratio of the speed of light in vacuum to that of an electron in the first Bohr orbit of hydrogen atom is

The maximum number of orbitals present in $n=4$ energy level of an atom and the maximum number of electrons with spin value $+\frac{1}{2}$ in the same orbitals are respectively

Choose the correct statements in reference to the photoelectric effect.
(A) There is no time lag between the striking of light and ejection of electrons from the metal surface.
(B) The number of electrons ejected is independent of the inten...

If the uncertainty in velocity is $\frac{1}{2 m} \sqrt{\frac{h}{\pi}}$, then the ratio of uncertainty in position and momentum is

When a radiation of 300 nm is shined on five metals, namely $\mathrm{Li}, \mathrm{Mg}, \mathrm{Ag}, \mathrm{Cu}$ and K , the number of metals that show photoelectric effect are

If the radius and energy of the second Bohr orbit of hydrogen atom is $r_2$ and $E_2$. respectively. The radius and energy of the third Bohr orbit will be $\_\_\_\_$ respectively.

The velocity $(v)$ of de-Broglie wave is given by
$$ \left[\begin{array}{l} v=\text { frequency } \\ m=\text { mass } \\ C=\text { velocity } \text { of } \text { light } \end{array}\right] $$

In hydrogen atom, the minimum energy required to excite an electron from 2nd orbit to the 3rd orbit is

The orbital angular momentum of an electron in $d$-orbital is equal to

The total number of spectral lines observed when electron returns from the 6th shell to the 2nd shell in hydrogen atom is

From the following sets of quantum numbers, which set is possible?

Maximum number of electrons in a subshell with $n=4$ and $l=3$ is

Which of the following results is not true about photoelectric effect?