Assertion : $A$ spectral line will be observed for a $2p_x - 2p_y$ transition.
Reason : The energy is released in the form of a wave of light when an electron drops from $2p_x$ to $2p_y$ orbital.

Given below are two statements:
Statement $I$: Rutherford's gold foil experiment cannot explain the line spectrum of hydrogen atom.
Statement $II$: Bohr's model of hydrogen atom contradicts Heisenberg's uncertainty principle.
In the light of the above statements,choose the most appropriate answer from the options given below:

Which of the following statement$(s)$ is (are) correct?

The shape of the probability distribution curve for the $2s$ orbital is .........

Identify the $INCORRECT$ statements from the following:
$A.$ Notation ${}_{12}^{24}Mg$ represents $24$ protons and $12$ neutrons.
$B.$ Wavelength of a radiation of frequency $4.5 \times 10^{15} \ s^{-1}$ is $6.7 \times 10^{-8} \ m$.
$C.$ One radiation has wavelength $\lambda_1 = 900 \ nm$ and energy $E_1$. Other radiation has wavelength $\lambda_2 = 300 \ nm$ and energy $E_2$. $E_1 : E_2 = 3 : 1$.
$D.$ Number of photons of light of wavelength $2000 \ pm$ that provides $1 \ J$ of energy is $1.006 \times 10^{16}$.
Choose the correct answer from the options given below:

Which of the following arrangements of electrons is most likely to be stable?