Meaning & use
valence electron
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Meaning
nouncountablechemistry
An electron in the outermost shell of an atom, which is the electron an atom can share, give away or take when it forms bonds with other atoms.
Grammar: Countable and usually plural: sodium has one valence electron, oxygen has six.
Patterns
- the number of valence electrons
- share valence electrons
Sodium has one valence electron, which it loses easily.
Carbon has four valence electrons, so it can form four bonds.
The noble gases have full outer shells, so they have a complete set of valence electrons.
Word forms
| plural | valence electrons |
|---|
Common combinations
- number of valence electrons
- The periodic table helps you find the number of valence electrons.
- share valence electrons
- Two hydrogen atoms share valence electrons to form a bond.
- lose a valence electron
- Metals tend to lose a valence electron when they react.
- valence electron shell
- The valence electron shell is the outermost layer of the atom.
- gain valence electrons
- Chlorine can gain valence electrons to complete its shell.
Synonyms and how they differ
- outer-shell electron
- Outer-shell electron is the plain description that means the same thing, and valence electron is the standard term in chemistry class.
- bonding electron
- Bonding electron refers to an electron actually taking part in a bond, so it is narrower than valence electron, which only needs to be available.
Opposites
Word family
Commonly confused: valence electron or core electron?
valence electron vs core electron
A core electron lies in an inner shell close to the nucleus and does not usually join in bonding, unlike a valence electron.
Practice
How many valence electrons does a neutral oxygen atom have?
Choose one answer.
Oxygen has six electrons in its outer shell. Eight would be a full shell, which is a tempting wrong answer, and oxygen reacts to reach it.
Make it your own
Write a sentence using “valence electron”, then check it and compare it with the examples above.