Electronegativity
Calculate electronegativity difference and bond type between any two elements using the Pauling scale. Free online chemistry calculator with interactive charts.
About This Calculator
The Electronegativity Calculator helps chemistry students, researchers, and professionals determine the electronegativity difference between any two elements and classify the resulting bond type. Using the widely accepted Pauling scale, the calculator computes Δχ = |χ₁ − χ₂| and classifies bonds as nonpolar covalent (Δχ < 0.4), polar covalent (0.4 ≤ Δχ < 1.7), or ionic (Δχ ≥ 1.7).
Electronegativity is a fundamental concept in chemistry that explains bond polarity, molecular geometry, and chemical reactivity. The calculator supports all 118 elements with their Pauling electronegativity values, and includes a custom mode for entering values from other scales like Mulliken, Allred-Rochow, or Sanderson. The interactive bar and pie charts provide visual comparison of the two elements' electronegativity values.
How Bond Type is Determined
The electronegativity difference is calculated using the formula Δχ = |χ₁ − χ₂|. If the difference is less than 0.4, electrons are shared almost equally in a nonpolar covalent bond. Between 0.4 and 1.7, the bond is polar covalent with partial charges (δ⁺ and δ⁻). Above 1.7, electron transfer occurs, forming an ionic bond. For example, NaCl (table salt) has a Δχ of 2.23, classifying it as ionic, while H₂O has a Δχ of 1.24 for O-H bonds, making them polar covalent.
Applications in Chemistry
Understanding electronegativity differences helps predict molecular polarity, solubility, boiling points, and chemical reactivity. Polar molecules tend to dissolve in polar solvents like water, while nonpolar molecules dissolve in nonpolar solvents. This calculator is ideal for general chemistry, organic chemistry, inorganic chemistry courses, and laboratory research where bond characterization is essential.
Frequently Asked Questions
What is electronegativity?
Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons. The Pauling scale is the most commonly used scale, with fluorine (3.98) being the most electronegative element and cesium (0.79) being the least electronegative.
How do you calculate the electronegativity difference?
Subtract the smaller electronegativity value from the larger one using the formula Δχ = |χ₁ − χ₂|, where χ₁ and χ₂ are the Pauling electronegativities of the two elements. The absolute value ensures the difference is always positive.
How do you determine bond type from electronegativity difference?
If Δχ is less than 0.4, the bond is nonpolar covalent (electrons shared equally). If Δχ is between 0.4 and 1.7, the bond is polar covalent (unequal sharing with a dipole moment). If Δχ is greater than 1.7, the bond is ionic (electron transfer occurs).
Which element has the highest electronegativity?
Fluorine (F) has the highest electronegativity on the Pauling scale with a value of 3.98. It is located in group 17, period 2 of the periodic table and is the most reactive nonmetal.
Which element has the lowest electronegativity?
Cesium (Cs) has the lowest electronegativity on the Pauling scale with a value of 0.79. Francium (Fr) is sometimes listed lower at 0.79 as well, but due to its radioactivity, cesium is generally considered the least electronegative stable element.
What is the electronegativity trend on the periodic table?
Electronegativity increases from left to right across a period due to increasing nuclear charge and decreasing atomic radius. It decreases from top to bottom down a group because atomic radius increases and electron shielding reduces nuclear attraction.
What is the electronegativity of hydrogen and oxygen?
Hydrogen has a Pauling electronegativity of 2.20, and oxygen has a Pauling electronegativity of 3.44. The electronegativity difference of 1.24 indicates that the O-H bond is polar covalent, which is why water molecules exhibit hydrogen bonding.
Can I use custom electronegativity values?
Yes, the calculator includes a Custom button for each element that lets you override the Pauling value with any electronegativity value you need, such as values from the Mulliken or Allred-Rochow scales for specialized calculations.