Electronegativity and the Polar Bond · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

When sharing electrons is unfair

Science · Matter & Materials · ages 15-16
Name ______________________   Date ____________

  1. Which element pulls shared electrons hardest of all?

    • Carbon
    • Oxygen
    • Fluorine

  2. In H-Cl, chlorine pulls harder than hydrogen. Which end is delta minus?

    • The hydrogen end
    • The chlorine end
    • Both ends equally

  3. Two identical atoms share a pair equally, as in H-H. What kind of bond is this?

    • Ionic
    • Nonpolar covalent
    • Polar covalent

  4. Why is carbon dioxide nonpolar overall?

    • Its two equal pulls point in opposite ways and cancel
    • Its bonds are nonpolar
    • It has only one bond

  5. Na-Cl differs by 2.1. What type of bond is this?

    • Nonpolar covalent
    • Polar covalent
    • Ionic

  6. Water is a bent molecule, so its bond pulls add up and the whole molecule is polar.

    Circle one:   True   False

  7. H-F differs by 1.9, much more than H-Cl at 0.9. What type is the H-F bond?

    • Polar covalent, still shared
    • Ionic, the electron moved over
    • Nonpolar, the pair sits in the middle

  8. A student says CO2 must be polar because each C-O bond is polar. What is the mistake?

    • Straight cancels 2 equal pulls
    • Carbon pulls harder than oxygen
    • CO2 has only one polar bond
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Answer key

For grown-ups. Fold this page away before handing over the rest.

When sharing electrons is unfair W1-mt_TwSlh2VvUT-s1

  1. Fluorine · Pull strength grows up and to the right, and fluorine sits at the top.
  2. The chlorine end · The stronger puller turns slightly negative, so chlorine is delta minus.
  3. Nonpolar covalent · A zero difference sits at the nonpolar end of the ruler.
  4. Its two equal pulls point in opposite ways and cancel · The straight shape points the two pulls against each other so they cancel.
  5. Ionic · A very large gap hands the electron over, which gives an ionic bond.
  6. True · The bent shape aims the pulls at an angle, so they combine.
  7. Polar covalent, still shared · Even a big gap can stay covalent, so the ruler stays rough.
  8. Straight cancels 2 equal pulls · Polar bonds do not guarantee a polar molecule when the shape cancels them.
Worksheet · LightMySky