What are the characteristics of different electron shells?

Electron shells are energy levels that differ in their distance from the nucleus, electron capacity, and energy.

Electron shells, also known as energy levels, are regions around the nucleus of an atom where electrons are most likely to be found. They are a fundamental concept in quantum mechanics, which is the branch of physics that deals with the behaviour of particles on the atomic and subatomic scale.

The first characteristic of electron shells is their distance from the nucleus. The first shell is closest to the nucleus, the second shell is further away, and so on. This distance is not fixed, but rather, it is a range within which the electrons in that shell are most likely to be found.

The second characteristic is the maximum number of electrons that each shell can hold. The first shell can hold up to 2 electrons, the second can hold up to 8, and the third can hold up to 8 as well. This is due to the number of available subshells and orbitals within each shell.

The third characteristic is the energy of the electrons in each shell. Electrons in shells closer to the nucleus have lower energy, while those in shells further away have higher energy. This is because the closer an electron is to the nucleus, the stronger the attractive force it experiences from the positively charged protons in the nucleus. As a result, it takes more energy to remove an electron from a shell closer to the nucleus than it does to remove one from a shell further away.

Lastly, the filling of electron shells follows a specific order, known as the Aufbau principle. This principle states that electrons occupy the lowest energy levels first. This means that the first shell must be completely filled before electrons can start filling the second shell, and so on. This order of filling helps to determine the chemical properties of an element.