Count valence electrons for atoms ions and formulas while exploring electron configurations Lewis dots periodic trends guided calculations examples quizzes and clear chemistry explanations.
Supports parentheses, nested groups, normal subscripts, Unicode subscripts, and charges like ^2−, 2−, +, or −.
Select an element to load it into the calculator. Main-group valence counts follow standard group trends.
Practice valence counts, groups, configurations, formulas, ions, and Lewis concepts.
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Valence electrons are electrons associated with an atom's outer region. They strongly influence bonding and chemical reactivity. For main-group elements, periodic-table groups provide a fast counting rule.
Groups 1 and 2 usually have one and two valence electrons. Groups 13 through 18 usually have three through eight. Helium is the important exception, because its first shell is complete with two electrons.
For a neutral molecule, add each atom's valence-electron contribution. Multiply each element's valence count by its atom count.
Total valence electrons = Σ(atom count × element valence electrons) − ionic charge.
A negative charge adds electrons because subtracting a negative charge increases the total. A positive charge removes electrons.
Main-group elements show a strong group pattern. Carbon in group 14 has four valence electrons. Oxygen in group 16 has six. Chlorine in group 17 has seven.
Transition metals are more complicated. Their outermost shell and chemically available d electrons may both matter. This tool therefore shows more than one useful count when needed.
Lewis symbols place dots around an element symbol to represent valence electrons. They help visualize bonding capacity and lone pairs.
The octet rule is a useful main-group guideline. Many atoms gain, lose, or share electrons toward eight valence-shell electrons. Hydrogen and helium follow a two-electron first-shell pattern instead.
Oxygen is in group 16, so a neutral oxygen atom has six main-group valence electrons.
Subtract a positive charge from the neutral total. Add the magnitude of a negative charge.
Yes. It parses grouped formulas such as Ca(OH)₂ and Al₂(SO₄)₃, including nested groups.
The phrase valence electrons can be context dependent for transition metals. Their ns and nearby d electrons may participate differently in bonding.
The Lewis view visualizes atomic valence dots. The formula calculator counts total valence electrons but does not infer a unique molecular Lewis structure.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.