Question

why do the negatively charged electrons not fall into the nucleus

Answer 1

Electrons are not little balls that can fall into the nucleus under electrostatic attraction. Rather,electrons are quantized wavefunctions that spread out in space and cansometimes act like particles in limited ways. An electron in an atom spreads out according to its energy.
That's why they not fall into the nucleus.

Answer 2

Electrons are not little balls that canfall into the nucleus under electrostatic attraction. Rather,electrons are quantized wavefunctions that spread out in space and can sometimes act like particles in limited ways. An electron in an atom spreads out according to its energy.