Potential Energy Curve of H₂: The Dance of Attraction and Repulsion

The video explains the formation of a hydrogen molecule using a potential energy vs. inter-nuclear distance graph. Initially, hydrogen atoms have nearly zero potential energy when far apart. As they approach, 1S orbitals overlap, leading to attractive forces and decreased potential energy. The minimum potential energy occurs at a bond length of 0.74 angstroms, where the molecule is stable. If the distance decreases further, nuclear repulsions increase, causing instability. Sigma bonds form through head-to-head or end-on overlap of orbitals.

What is the potential energy of individual hydrogen atoms when they are far apart?

• High potential energy

• Infinite potential energy

• Zero potential energy

• Negative potential energy

What happens to the potential energy as two hydrogen atoms come closer and their 1S orbitals begin to overlap?

• It increases

• It decreases

• It remains constant

• It becomes zero

At what inter-nuclear distance is the hydrogen molecule most stable?

• 0.84 angstroms

• 0.74 angstroms

• 0.64 angstroms

• 0.54 angstroms

What causes the potential energy to reach a maximum value when the distance between hydrogen atoms is less than 0.74 angstroms?

• Decreased nuclear attractions

• Increased electron-electron repulsions

• Increased nuclear-nuclear repulsions

• Decreased orbital overlap

Which of the following orbital overlaps can form a sigma bond?

• 2S and 2P orbital

• 1S and 1D orbital

• 1S and 1P orbital

• 2P and 3P orbital