What an electronegativity chart shows
An electronegativity chart lists Pauling electronegativity values, written as \( \chi \), for individual elements. These values indicate how strongly an atom attracts shared electrons in a chemical bond. When two bonded atoms have different electronegativities, electron density shifts toward the more electronegative atom and the bond becomes more polar.
Electronegativity reference values (Pauling scale)
On wider screens, the reference values are arranged in multiple side-by-side columns instead of one long single-column table. On narrow screens, the columns wrap naturally.
| Element | \( \chi \) |
|---|---|
| H | 2.20 |
| He | — |
| Li | 0.98 |
| Be | 1.57 |
| B | 2.04 |
| C | 2.55 |
| N | 3.04 |
| Element | \( \chi \) |
|---|---|
| O | 3.44 |
| F | 3.98 |
| Ne | — |
| Na | 0.93 |
| Mg | 1.31 |
| Al | 1.61 |
| Si | 1.90 |
| Element | \( \chi \) |
|---|---|
| P | 2.19 |
| S | 2.58 |
| Cl | 3.16 |
| Ar | — |
| K | 0.82 |
| Ca | 1.00 |
| Fe | 1.83 |
| Element | \( \chi \) |
|---|---|
| Cu | 1.90 |
| Zn | 1.65 |
| Br | 2.96 |
| I | 2.66 |
| Au | 2.54 |
| Pb | 2.33 |
How \( \Delta \chi \) is calculated
The electronegativity value for each atom is taken from the chart, and the numerical difference is calculated with
\[ \Delta \chi = \left|\chi_A - \chi_B\right| \]
Introductory chemistry commonly uses these approximate cutoffs: \( \Delta \chi < 0.4 \) for nonpolar covalent bonding, \( 0.4 \le \Delta \chi \le 1.7 \) for polar covalent bonding, and \( \Delta \chi > 1.7 \) for bonds with strong ionic character.
Worked examples and interactive comparison
Selecting any row below updates the visualization above.
| Bond | \( \chi \) values | \( \Delta \chi \) | Classification | Direction of electron-density shift |
|---|---|---|---|---|
| H–Cl | H: 2.20, Cl: 3.16 | 0.96 | Polar covalent | Toward Cl |
| Na–Cl | Na: 0.93, Cl: 3.16 | 2.23 | Predominantly ionic | Toward Cl |
| C–H | C: 2.55, H: 2.20 | 0.35 | Nonpolar or very weakly polar | Slightly toward C |
| C–O | C: 2.55, O: 3.44 | 0.89 | Polar covalent | Toward O |
H–Cl: \( \Delta \chi = |2.20 - 3.16| = 0.96 \)
Na–Cl: \( \Delta \chi = |0.93 - 3.16| = 2.23 \)
C–H: \( \Delta \chi = |2.55 - 2.20| = 0.35 \)
C–O: \( \Delta \chi = |2.55 - 3.44| = 0.89 \)
The same procedure applies to any bond shown on an electronegativity chart: read the two Pauling values, calculate \( \Delta \chi \), and place the dipole toward the more electronegative atom.