Question

Which of the following relation is untrue based on Bohr's model of the atom?

• A. Velocity of electron $\propto \frac{1}{n}$
• B. Frequency of revolution $\propto \frac{1}{n^3}$
• C. Radius of orbit $\propto n^{2}Z$
• D. Energy of an electron in $n^{th}$orbit $\propto Z^2$

Answer 1

The correct option is C Radius of orbit $\propto n^{2}Z$

According to Bohr's theory,
$r=r_0\left(\frac{n^2}{Z}\right)$
So, the radius is directly proportional to square of n and inversely proportional to atomic number Z. Similarly, velocity is proportional to $\frac{Z}{n}$. Frequency is proportional to $\frac{Z^2}{n^3}$ and energy of an electron in $n^{th}$ orbit is $\frac{Z^2}{n^2}$.