Atomic Structure - Result Question 19

Match the Columns

19. According to Bohr’s theory,

$E _n=$ Total energy $\quad K _n=$ Kinetic energy

$V _n=$ Potential energy $\quad r^{n}=$ Radius of $n$th orbit

(2006, 6M)

Match the following :

Column I Column II
A. $V _n / K _n=$ ? p. 0
B. If radius of $n$th orbit $\propto E _n^{x}, x=$ ? q. -1
C. Angular momentum in lowest
orbital
r. -2
D. $\dfrac{1}{r^{n}} \propto Z^{y}, y=?$ s. 1
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Answer:

Correct Answer: 19. $ A \rightarrow r; \hspace{2mm} B \rightarrow q; \hspace{2mm} C \rightarrow p; \hspace{2mm} D \rightarrow s $

Solution:

  1. A. $V _n=-\dfrac{1}{4 \pi \varepsilon _0}\left(\dfrac{Z e^{2}}{r}\right)$

$ \begin{aligned} K _n & =\dfrac{1}{8 \pi \varepsilon _0}\left(\dfrac{Z e^{2}}{r}\right) \\ \Rightarrow \quad \dfrac{V _n}{K _n} & =-2 \quad -(r) \end{aligned} $

B. $E _n=-\dfrac{Z e^{2}}{8 \pi \varepsilon _0 r} \propto r^{-1}$

$ \Rightarrow \quad x=-1 \quad -(q) $

C. Angular momentum $=\sqrt{l(l+1)} \dfrac{h}{2 \pi}=0$ in $1 s$-orbital $\quad -(p)$

D. $r _n=\dfrac{a _0 n^{2}}{Z} \Rightarrow \dfrac{1}{r _n} \propto Z \quad -(s)$