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 α-particles were bombarded on the gold foil, compute the number of α-particles that would deflect at angles less than 500.

Percentage of α-particles deflected by more than 50 degrees =1% of α-particles.

Percentage of α-particles deflected less than 50 degrees =100–1 = 99%


Number of α-particles bombarded = 1 mole = 6.022×1023 particles


Number of particles that deflected at an angle less than 500



= 5.96 × 1023


Hence, the number of particles that deflected at an angle less that 50°is equal to 5.961023



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