As you know, electrons are always moving. They spin very quickly around the nucleus of an atom. As the electrons spin, they can move in any direction, as long as they stay in their shell. Any direction you can imagine - upwards, downwards, or sidewards - electrons can do it. The atomic shell or orbital is the distance from the nucleus that the electron spins. If you are an electron in the first shell you are always closer to the nucleus than the electrons in the second shell.

Electrons can spin around the nucleus of an atom in any direction

ORBITAL BASICS

Let's cover some basics of atomic orbitals.
1. A shell is sometimes called an orbital or energy level.
2. Shells are areas that surround the center of an atom.
3. The center of the atom is called the nucleus.
4. Electrons live in something called shells.
5. Each of those shells has a name.

There are a couple of ways that atomic orbitals are named. You may have heard of the SPDF system before. Chemists also use letters to name the orbitals around a nucleus. They use the letters "k,l,m,n,o,p, and q". The "k" shell is the one closest to the nucleus and "q" is the farthest away.

Orbitals of an atom with letter designations

Not all shells hold the same number of electrons. For the first eighteen elements, there are some easy rules. The k-shell only holds two electrons. The l-shell only holds eight electrons. The m-shell only holds eight electrons (for the first eighteen elements). The m-shell can actually hold up to 18 electrons as you move farther along the periodic table. The maximum number of electrons you will find in any shell is 32.

WHERE ARE THE ELECTRONS?

We've been telling you that electrons reside in specific shells or move in specific directions. We can't really tell you exactly where an electron is at any moment in time. We can only approximate, or guess, where an electron is located. According to something called quantum theory, an electron can be found anywhere around the nucleus. Using advanced math, scientists are able to approximate, or guess, that electrons are in general areas. These general areas are called the shells.

RELATED LINKS

- Biology4Kids: Scientific Method
- Geography4Kids: Energy Quanta
- Geography4Kids: Magnetic Fields
- Physics4Kids: Modern Physics
- Physics4Kids: Nuclear Physics

-	Overview
-	Structure
>	Orbitals
-	Ions
-	Electrons
-	Isotopes
-	Neutrons
-	Bonding
-	Compounds
-	Compound Names
-	Advanced Ideas
	MORE CHEMISTRY TOPICS

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