【People's Education Press】High School Chemistry - Elective Compulsory Course, Second Volume: Structure Determines Properties

The microscopic world is not a chaotic jumble—it is akin to intricate architectural art. This lesson aims to establish“Structure Determines Properties”as a fundamental chemical principle. Covalent bonds are not merely interactions through shared electron pairs between atoms—they are the very foundation of molecular frameworks.

Core Aesthetic Principles

Geometric Diversity: The strained tetrahedral structure of $P_4$ makes it highly flammable; the crown-like shape of $S_8$ provides stability in elemental balance; and the highly symmetric octahedral geometry of $SF_6$ makes it an excellent insulator.
Energy Balance: Molecular geometries are not randomly formed—they are optimized to achieve balanced electron distribution and minimize total energy.
Cross-Scale Transfer: From simple $C_{60}$ buckyballs to ATP synthase embedded in lipid bilayers, ATP synthasethe precision of structural integrity determines the high efficiency of proton transport and energy conversion in living systems.

Deep Thinking

Why does $P_4$ readily ignite in air? Observe its 60° bond angle—far below the ideal arrangement for phosphorus atoms—generating massive 'angular strain' that makes chemical bonds prone to breakage, releasing energy and transforming into more stable configurations.

QUESTION 1

Which of the following statements about molecules is incorrect? ( )

Molecules are formed by atoms bonded together via covalent bonds

The essence of a covalent bond is the sharing of electron pairs between atoms

All molecules have a specific spatial geometric configuration

A molecule’s properties are entirely determined by the types of atoms it contains, regardless of their spatial arrangement

QUESTION 2

Which statement about the propylene ($CH_3CH=CH_2$) molecule is incorrect? ( )

The molecule contains both single and double bonds

All carbon atoms lie in the same plane

The covalent bonds in the propylene molecule are formed by shared electron pairs

The spatial structure of the molecule has no effect on its physical properties

QUESTION 3

You’ve learned about many substances’ chemical properties—please provide examples discussing how molecular structure influences chemical behavior.

For example, ethanol and dimethyl ether have the same molecular formula but different structures, resulting in distinct chemical reactivity

QUESTION 4

Briefly explain how structural symmetry differently affects the stability of $P_4$ and $SF_6$ molecules.

P4 has high strain and is reactive; SF6 has high symmetry and is extremely stable

QUESTION 5

Why is the specific structure of ATP synthase crucial for its biological function?

Specific protein folding creates proton channels and rotational motor units