What makes a valence electron

Skip to main content. Electrons in Atoms. Search for:. Valence Electrons Learning Objectives Define valence electron. Be able to indicate valence electrons when given the electron configuration for an atom. What makes a particular element very reactive and another element non-reactive? Summary Valence electrons are the outer-shell electrons of an atom.

Valence electrons determine the reactivity of an atom. A valence electron is an electron that is associated with an atom, and that can participate in the formation of a chemical bond; in a single covalent bond, both atoms in the bond contribute one valence electron in order to form a shared pair.

The presence of valence electrons can determine the element's chemical properties and whether it may bond with other elements: For a main group element, a valence electron can only be in the outermost electron shell. An atom with one or two valence electrons more than a closed shell is highly reactive, because the extra valence electrons are easily removed to form a positive ion. An atom with one or two valence electrons fewer than a closed shell is also highly reactive, because of a tendency either to gain the missing valence electrons thereby forming a negative ion , or to share valence electrons thereby forming a covalent bond.

Like an electron in an inner shell, a valence electron has the ability to absorb or release energy in the form of a photon. An energy gain can trigger an electron to move jump to an outer shell; this is known as atomic excitation. Or the electron can even break free from its associated atom's valence shell; this is ionization to form a positive ion. When an electron loses energy thereby causing a photon to be emitted , then it can move to an inner shell which is not fully occupied.

Electrons are negatively charged subatomic particles surrounding the nucleus of an atom in shells. In chemistry, a group refers to two or more atoms that are specifically arranged. Groups are also called radicals. Free radicals are unstable, highly reactive atoms or molecules that have unpaired valence electrons.

Atoms may be teeny-tiny, but they have a lot going on beneath the surface. During the early s, Gilbert N. Lewis an American chemist and professor at University of California, Berkeley significantly contributed to our understanding of valence electrons.

Some fundamentals: atoms are made up of neutrons , protons , and electrons. The nucleus or the center of an atom consists of neutrons and protons. Electrons surround the nucleus in shells.

The shell closest to the nucleus can hold two electrons. The second shell can hold up to eight electrons, the third up to Atoms—perhaps not unlike people?! They bond with other unstable atoms! There are two basic kinds of bonds:. The first kind is called a covalent bond. Covalent bonds happen when two atoms bond together by sharing valence electrons.

A single hydrogen atom only has one outer shell and one valence electron.