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

Which one is the wrong statement?

Which of the following violates the Aufbau principle and Hund's rule?

Among the following,the correct statement$(s)$ for electrons in an atom is(are):
$A$. Uncertainty principle rules out the existence of definite paths for electrons.
$B$. The energy of an electron in $2s$ orbital of an atom is lower than the energy of an electron that is infinitely far away from the nucleus.
$C$. According to Bohr's model,the most negative energy value for an electron is given by $n=1$,which corresponds to the most stable orbit.
$D$. According to Bohr's model,the magnitude of velocity of electrons increases with increase in values of $n$.

Match the items in List-$I$ with the items in List-$II$.

List-$I$	List-$II$
$A$. Nodes	$I$. Three dimensional shape of the orbital
$B$. Subsidiary quantum number	$II$. Significant only for motion of microscopic objects
$C$. White light	$III$. $|\psi|^2$ is zero
$D$. Heisenberg uncertainty principle	$IV$. Spin state of electron
	$V$. Continuous spectrum

What is the ratio of time periods in the $3^{rd}$ orbit of $H^{-}$ atom to the $2^{nd}$ orbit of $He^{+}$ ion?