Chemistry · Chemical Bonding · NEET
Look at the two atoms. If they are the SAME element (H-H, Cl-Cl, N≡N), the electronegativity difference is zero, sharing is equal, and the bond is nonpolar. If they are DIFFERENT elements (H-F, O-H, C-Cl), one pulls harder, so the bond is polar. In short: same atom = nonpolar bond, different atom = polar bond.
They are partial charges, not full charges. In H-F, fluorine is more electronegative, so it pulls the shared electron pair closer and becomes slightly negative (δ-). Hydrogen loses a bit of electron density and becomes slightly positive (δ+). δ means 'partial', so it is much smaller than the +1 or -1 charge of a real ion. This partial charge separation is what makes the bond polar and gives it a dipole moment.
No. This is the biggest confusion. A molecule can have polar bonds but still be a nonpolar molecule if the bonds are arranged symmetrically. In CO2, both C=O bonds are polar, but they point in exactly opposite directions, so the two bond dipoles cancel and the net dipole moment is zero. So the molecule is nonpolar even though each bond is polar. Bond polarity and molecule polarity are two different steps.
Polarity depends on how unequally the shared pair is pulled. A bigger electronegativity difference means one atom grabs the electron pair much harder, so the charge separation (δ+ and δ-) is larger, and the bond is more polar. That is why H-F is more polar than H-I: fluorine is far more electronegative than hydrogen, while iodine is much closer. When the difference is very large, the bond becomes ionic instead of covalent.
NCERT says no. A perfectly nonpolar (100% covalent) bond only happens between two identical atoms, like H-H. Every bond between different atoms has some ionic character because of unequal sharing. Likewise, no bond is 100% ionic; even ionic bonds have some covalent character. Real bonds sit on a scale between the two extremes.
Which of the following molecules is non-polar in nature?
Try the real previous-year questions from this chapter — each with the answer and a full solution.
A covalent bond between two atoms of different electronegativity, where the shared electron pair is pulled more toward the more electronegative atom, creating δ+ and δ- ends and a dipole moment.
Nonpolar: H-H, Cl-Cl, O=O, N≡N (same atoms). Polar: H-F, H-Cl, O-H, C-O (different atoms). H-F is a classic polar bond because fluorine is far more electronegative than hydrogen.
No. In a nonpolar covalent bond the sharing is equal, so there is no charge separation and the bond dipole moment is zero. Only polar bonds have a bond dipole moment.
NEET regularly asks whether a molecule is polar or nonpolar and to order dipole moments (asked in 2019, 2020, 2021, 2023, 2024, 2025). You must first decide if each bond is polar, then use the shape to see if the dipoles cancel. Getting this two-step logic right earns easy marks.
