Atomic Structure - Result Question 25
####1. Which one of the following about an electron occupying the $1 s$-orbital in a hydrogen atom is incorrect? (The Bohr radius is represented by $a _0$ )
(2019 Main, 9 April II)
(a) The electron can be found at a distance $2 a _0$ from the nucleus.
(b) The magnitude of the potential energy is double that of its kinetic energy on an average.
(c) The probability density of finding the electron is maximum at the nucleus.
(d) The total energy of the electron is maximum when it is at a distance $a _0$ from the nucleus.
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Answer:
Correct Answer: 1. (d)
Solution:
- Statement (d) is incorrect. For $1 s$-orbital radial probability density $\left(R^{2}\right)$ against $r$ is given as:
For $1 s$-orbital, probability density decreases sharply as we move away from the nucleus.
The radial distribution curves obtained by plotting radial probability functions $v s r$ for $1 s$-orbital is
The graph initially increases and then decreases. It reaches a maximum at a distance very close to the nucleus and then decreases. The maximum in the curve corresponds to the distance at which the probability of finding the electron in maximum.
