Structure of atom practice · Mixed difficulty

An ion has 18 electrons in the outermost shell, it is

Choose the correct energy order for $2 s$ orbital

What will be the wave length of an electron moving with $\frac{1}{10}$ th of velocity of light?

Which one of the following sets of quantum numbers is possible

According to Bohr's theory, the electronic energy of $\mathrm{H}$-atom in Bohr's orbit is given by

Which of the following particle is not deflected in the magnetic field?

Amongst the following statements, select the set having statements which was proposed by Dalton.
(1) All the atoms of a given element have identical properties including identical mass. Atoms of different elements differ in mass.
(2) When gases combine or reproduced in a chemical reaction they do so in a simple ratio by volume provided all gases are at the same $\mathrm{T} \,\&\, \mathrm{P}$
(3) Chemical reactions involve reorganization of atoms. These are neither created nor destroyed in a chemical reaction.
(4) Matter consists of indivisible atoms

Assertion: The configuration of $Be$-atom cannot be $1 s^2 3 s^2$.
Reason: The electrons enter the various orbitals in the order of increasing energy.

Statement (S): Monochromatic X-rays fall on lighter elements such as carbon and show scattering under the name of Compton effect.

Explanation (E): $\lambda_{\text {scattered }}$ light is always lower than $\lambda_{\text {incident }}$ light.

Sodium exists in two isotopic forms ${Na}^{23}$ and ${Na}^{24}$ in nature. If ${Na}^{24}$ is present at the abundance of $25 \%$ in the nature. The average atomic mass of the element is :-

Which wavelength falls in a X-rays region?

Which of the following gave the idea of nucleus of the atom?

The momentum of a particle which has a de-Broglie wavelength of $0.1 \mathrm{~nm}$ is

The energy of the electron in the second and the third Bohr's orbits of the hydrogen atom is $-5.42 \times 10^{-12}$ erg and $-2.41 \times 10^{-12}$ erg respectively. Calculate the wavelength of the emitted radiation when the electron drops from the third to the second orbit.

The electronic transition from $n=2$ to $n=1$ will produce the shortest wavelength in (where, $n=$ principal quantum number)

According to the Bohr theory, which of the following transitions in the Hydrogen atom will give rise to the least energetic photon

The maximum number of electrons that can be identified with the quantum number $\ell=2$ for $\mathrm{Fe}^{3+}$ ion will be

The number of nodal planes ' $5 d$ ' orbital has is

The wave function ( $\Psi$ ) of 2 s is given by $\Psi_{2 s}=\frac{1}{2 \sqrt{2 \pi}}\left(\frac{1}{a_0}\right)^{1 / 2}\left(2-\frac{r}{a_0}\right) e^{-f / 2 a_0}$

At $r=r_0$, radial node is formed. Thus, $r_0$ in terms of $a_o$

The set of quantum numbers $n=3, l=0, m=0, s=-1 / 2$ belongs to the element

The $\mathrm{\lambda }$ for ${H_\alpha }$ line of Balmer series is  6500 Å. Thus $\mathrm{\lambda }$ for ${H_\beta }$ line of Balmer series is :

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

Which of the following is Heisenberg uncertainty principle?

Which one of the following is considered as the main postulate of Bohr’s model of atom

The ionisation energy of hydrogen atom is 13.6 eV. What will be the ionisation energy of $\mathrm{H}{\mathrm{e}^ + }$?

The total values of magnetic quantum number of an electron when the value of n=2 is:

The frequency of radiation absorbed or emitted when transition occurs between two stationary states with energies $E_1$ (lower) and $E_2$ (higher) is given by

The electrons identified by 517 ‘n’ and ‘l’
$(i)n = 4,\,l = 1,\,(ii)\,n = 4,\,l = 0,\,(iii)\,n = 3,\,l = 2\,,\,(iv)\,n = 3,\,l = 1$ , Can be placed in order of increasing from lowest to highest is

$\alpha$-particles can be detected by using

Electrons and nucleus are held together by