To find:
Which of the given statements is not true.
Step-by-step explanation:
Atom is considered the basic unit of matter. The electron is one of the elemental particles. But the atom is considered to be the basic unit of matter. Thus statement A is not true.
The electrons revolve around the nucleus of an atom. Thus their path is not necessarily straight. Thus statement B is true.
The electrons have discrete sets of energy levels. And revolve around the nucleus. It can be considered as the clouds around the nucleus. Thus statement C is true.
The electrons have negative charges. Thus statement D is true.
Final answer:
Thus only statement A is not true about the electron.
Thus the correct answer is option A.