Electron shell facts for kids

Example of the Hydrogen atom: it has one electron shell and one electron.

Imagine an atom as a tiny solar system. At its center is the nucleus, like the sun. Around it, tiny particles called electrons zoom around. An electron shell is like a special path or energy level where these electrons orbit the nucleus.

Every atom has one or more electron shells. Each shell can hold a different number of electrons. These shells are important because they help us understand how atoms behave. They also show how electrons are arranged in an atom.

The idea of electron shells came from the Bohr model. This model, created by Niels Bohr, suggested that electrons orbit the nucleus at specific distances. These orbits looked like "shells."

What is a Valence Shell?

The valence shell is the outermost electron shell of an atom. The electrons in this shell are called valence electrons. These are the electrons that are most likely to be involved when atoms join together to form molecules.

For example, noble gases like neon or argon are very stable. This is because their outermost shell usually has eight electrons. (The only exception is helium, which has two electrons in its only shell). This idea is part of the octet rule. It says that atoms often try to get eight electrons in their outer shell. This makes them stable, like noble gases. This rule is mostly for the main elements in the second and third rows of the periodic table.

For some special atoms called transition metals, the valence shell can hold up to 18 electrons. This is known as the eighteen electron rule.

Understanding Electron Sub-shells

Inside each electron shell, there are smaller groups called electron sub-shells. Think of them as different rooms within a house (the shell). These sub-shells are named with letters: s, p, d, f, g, h, i, and so on.

Each type of sub-shell can hold a specific number of electrons:

• s sub-shells can hold up to 2 electrons.
• p sub-shells can hold up to 6 electrons.
• d sub-shells can hold up to 10 electrons.
• f sub-shells can hold up to 14 electrons.
• And so on, with each new letter adding 4 more electrons to its capacity.

These sub-shells help scientists understand the exact arrangement of electrons in an atom. This arrangement is called the electron configuration.

Images for kids

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  3D views of some hydrogen-like atomic orbitals showing where electrons are likely to be found.

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  This chart shows the order in which electron shells and sub-shells are filled.

See also

In Spanish: Capa electrónica para niños