Question

Consider the following figures A and B indicating the distribution of charge density (electron probability ${\psi }^2$ with distance $r$).
Select the correct statement:

• A. A and B both are for $1s$
• B. A and B are both for $2s$
• C. A is for $2s$, B is for $1s$
• D. A is for $1s$, B is for $2s$

Answer 1

The correct option is D A is for $1s$, B is for $2s$

The point at which the probability function acquires zero value is known as a radial node.
The number of radial node $=n-l-1$
where, n = principal quantum number
$l$ = azimuthal quantum number
In graph A, there is no radial node i.e $1s$ because $1s(n-l-1=1-0-1=0)$ has no node.
In graph B, there is one radial node i.e $2s$ because $2s(n-l-1=2-0-1=1)$ has one radial node.