Valence shell

Definition

The valence shell is the outermost electron shell of an atom that contains electrons. Electrons in this shell are involved in chemical bonding and determine the chemical properties of the element.

5 Must Know Facts For Your Next Test

1. The valence shell can hold a maximum number of electrons determined by $2n^2$, where $n$ is the principal quantum number.
2. Elements with a full valence shell are typically inert gases, which are chemically stable.
3. The number of electrons in the valence shell determines an element's group in the periodic table.
4. Atoms tend to gain, lose, or share electrons to achieve a full valence shell, often following the octet rule.
5. Valence electrons play a crucial role in forming covalent and ionic bonds.

Review Questions

• What role does the valence shell play in determining an element's chemical properties?
• How does the number of electrons in the valence shell relate to an element's position on the periodic table?
• Why are elements with a full valence shell generally unreactive?

Related terms

Electron Configuration: The distribution of electrons among the various atomic orbitals; it describes how electrons are arranged around the nucleus.

Octet Rule: A principle stating that atoms tend to bond in such a way that each atom has eight electrons in its valence shell, achieving a noble gas configuration.

Principal Quantum Number: $n$ indicates the main energy level occupied by an electron and its relative distance from the nucleus.