It has been found that nature behaves very differently from what Newtonian physics led us to believe. These differences are insignificant for large, macroscopic events, but become startlingly evident on the atomic scale. First you need to know what quantized means. In everyday life the cost of goods is quantized that is, the cost of an item cannot be any arbitrary amount, but must be an integral multiple of one penny the smallest unit of money. In physics it is evident that matter is quantized you cannot gather an arbitrary mass of iron, but can collect only integral multiples of the mass of one iron atom.
Charge is quantized all charge is a multiple of the elementary electron charge.
For an individual hydrogen atom, this has enormous implications. Recall problem 9 of chapter 18. Find a numerical solution. The model of an atom we are discussing is called the Bohr model after Neils Bohr who proposed it early in this century. It was used by him to describe and predict the spectrum of hydrogen.