[Physics] Why does velocity of electron increases with increase atomic number in the Bohr model of the hydrogen and hydrogen like atoms

atomic-physics

I already know mathematical proof which states velocity of electron increases with increase in atomic number,but what is the intuition behind it?

Best Answer

The same reason the Earth would move faster should the mass of the sun increase: centripetal force grows. In the case of Bohr's model, the force grows as $\sim Z$,

$$ F_e = \frac{k Ze^2}{r^2} $$

Newton's law thus results in

$$ \frac{mv^2}{r} = F_e = \frac{k Ze^2}{r^2} $$

leading to $v \sim Z^{1/2}$

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