An electron cannot stay inside the nucleus of an atom because of fundamental principles of quantum mechanics and the nature of the forces involved.
In an atom, the nucleus is composed of positively charged protons and usually neutral or slightly negatively charged neutrons. Electrons, on the other hand, have a negative charge. According to the laws of electromagnetic force, like charges repel each other, while opposite charges attract.
Quantum mechanics describes the behavior of particles at the atomic and subatomic levels. It introduces the concept of energy levels or shells in which electrons can occupy around the nucleus. These energy levels are characterized by specific energy values. The lowest energy level, called the ground state, is closest to the nucleus.
The distribution of electrons around the nucleus follows a set of rules known as the Pauli exclusion principle and the Aufbau principle. The Pauli exclusion principle states that no two electrons in an atom can have the same set of quantum numbers, which includes properties like spin and energy. The Aufbau principle states that electrons fill the available energy levels starting from the lowest energy level, with each level accommodating a specific maximum number of electrons.
Since electrons have a negative charge, they are attracted to the positively charged nucleus. However, according to quantum mechanics, electrons occupy discrete energy levels or orbitals around the nucleus. These orbitals correspond to specific distances from the nucleus and are associated with specific energy values. The electrons are constantly in motion within these orbitals, but they cannot occupy the same space at the same time due to the Pauli exclusion principle.
The lowest energy level, which is closest to the nucleus, can accommodate a maximum of two electrons. As electrons fill higher energy levels, they occupy different orbitals, avoiding any overlap or direct contact with each other. The forces between the electrons and the nucleus, as well as the forces between electrons themselves, keep them distributed in these energy levels and prevent them from collapsing into the nucleus.
In summary, the laws of electromagnetism, the principles of quantum mechanics, and the specific distribution of electrons in energy levels around the nucleus prevent electrons from staying inside the nucleus of an atom. The nature of these forces and the discrete energy levels of electrons dictate their behavior and organization within an atom.