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Intramolecular Force and Potential Energy

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A bond is a balance of forces read off a potential-energy curve. As two atoms approach, attraction lowers the energy until repulsion between the nuclei takes over. The lowest point sets the bond length, and the depth of the well is the bond energy, the energy needed to pull the atoms fully apart.

UNIT 2 TOPIC 2.2 • INTRAMOLECULAR FORCE AND POTENTIAL ENERGY BOND WELL Potential energy vs. internuclear distance — the shape of a chemical bond. POTENTIAL-ENERGY CURVE 0 POTENTIAL ENERGY INTERNUCLEAR DISTANCE, r Dₑ bond energy bond length, rₑ REPULSION clouds overlap, nuclei push apart ATTRACTION nuclei pull the atoms together PE ≈ 0 TOO CLOSE r < rₑ Repulsion dominates — electron clouds overlap, nuclei push apart. High PE. AT MINIMUM r = rₑ Attraction and repulsion balance — most stable, lowest potential energy. FAR APART r → ∞ Weak attraction, almost no interaction between atoms. PE ≈ 0. BOND-ORDER TREND single < double < triple → bond length decreases → bond energy increases ION-PAIR STRENGTH Higher charges & smaller ions → stronger attraction. MgO > NaCl MOTION FROM MINIMUM far apart → closer → minimum → too close. Either way from rₑ raises PE. TAKEAWAY A stable bond sits at the PE minimum; its depth is the bond energy, and higher bond order → shorter, stronger bond. AP Chemistry · Unit 2 · Compound Structure & Properties
A bond is a balance of attraction and repulsion. The potential-energy curve dips to a minimum at the bond length (rₑ); the depth of that well is the bond energy. Pull the atoms apart or push them together and the energy rises.
Bond Well · Open the sandbox →

The curve encodes two ideas at once: where the atoms sit (the bond length, at the minimum) and how tightly they are held (the well depth). Shorter, deeper wells mean stronger bonds. Reading distance and energy off the same curve, without confusing them, is the whole skill.

The work

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Lesson
Bond Energy Curves ›

The potential-energy curve of a bond fixes both its length and its strength. The lesson reads bond length off the minimum and bond energy off the well depth, then closes with a ten-scenario applet.

Skill check · 10 scenarios
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Diagnostic
10-item topic check ›

Ten items on reading a bond's potential-energy curve: locating the bond length at the energy minimum, reading bond energy as the well depth, and telling stronger from weaker bonds by the shape of the well.

Not started · 10 items · ~15 min
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Targeted Practice
Drill a single misconception ›

Pick one of the failure modes you missed and drill it on its own. The round is adaptive: two correct in a row clears the misconception and moves you to the next.

Take the diagnostic to identify your misconceptions
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