Question

Question 43
In the gold foil experiment of Geiger and Marsden, that paved the way for Rutherford's model of an atom, $1.00\%$ of the alpha-particles were found to deflect at angles $>{50}^{\circ }$. If one mole of alpha-particles were bombarded on the gold foil, compute the number of alpha-particles that would deflect at angles less than ${50}^{\circ }$.

Answer 1

% of α-particles deflected more than ${50}^{\circ }$ =1% of α-particles.
% of α-particles deflected less than ${50}^{\circ }$ =100 – 1 = 99%
Number of α-particles bombarded = 1 mole = $6.022\times {10}^{23}$ particles
Number of particles that deflected at an angle less than ${50}^{\circ }$,

$=\frac{99}{100}\times 6.022\times {10}^{23}$
$=5.96\times {10}^{23}$