In the gold foil experiment of Geiger and Marsden, that paved the way for Rutherford's model of an atom, ≈1.00% of the α-particles were found to deflect at angles > 50°. If one mole of alpha particles were bombarded on the gold foil, compute the number of alpha particles that would deflect at angle less than 50°.

% of α-particles deflected more than 50°  = 1% of α-particles.
% of α-particles deflected less than 50°    = 100 – 1 
                                                                          = 99%
Number of α-particles bombarded = 1 mole = 6.022×10²³  particles
Number of particles that deflected at an angle less than 50° =  $\frac{99}{100} \times 6.03\times {10}^{23}$
                                                                                                           $=\frac{596.97}{100}\times {10}^{23}$
                                                                                                            $= 5.96\times {10}^{23}$  
 Therefore, $5.96\times {10}^{23}$ is the number of alpha-particles that would deflect at angles less than $50$°.