Structure Of Atom Ques 10

10. The Bohr orbit radius for the hydrogen atom $(n=1)$ is approximately $0.530 $ $\AA$. The radius for the first excited state $(n=2)$ orbit is (in $\AA$ )

[1998]

(a) $0.13$

(b) $1.06$

(c) $4.77$

(d) $2.12$

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Answer:

Correct Answer: 10.(d)

Solution:

  1. (d) Radius of hydrogen atom $=0.530 \AA$, Number of excited state $(n)=2$ and atomic number of hydrogen atom $(Z)=1$. We know that the Bohr radius.

$(r)=\frac{n^{2}}{Z} \times$ Bohr Radius of atom $=\frac{(2)^{2}}{1} \times 0.530$ $=4 \times 0.530=2.12 $ $\AA$