Properties are classified into two main groups.

Properties are classified into two main groups.

• A. Physical and Chemical
• B. Mechanical and Thermal
• C. Structural and Chemical
• D. Electrical and Optical

Answer: (A)

Two broad ways to think about material behavior are physical properties and chemical properties. Physical properties are things you can observe or measure without changing what the material is—think density, melting point, color, electrical resistivity, and hardness. Chemical properties describe how a material behaves in reactions or how its composition can change, such as reactivity with acids, flammability, corrosion tendency, or how it oxidizes. That’s why the correct choice is physical and chemical. It captures the standard division used to categorize how materials respond—either without a change in composition or through chemical transformation. The other pairings describe specific kinds of properties, not the broad two-group framework: mechanical and thermal are kinds of physical properties, structural is not a primary binary division, and electrical and optical are specific property types that fall under physical properties.

Two broad ways to think about material behavior are physical properties and chemical properties. Physical properties are things you can observe or measure without changing what the material is—think density, melting point, color, electrical resistivity, and hardness. Chemical properties describe how a material behaves in reactions or how its composition can change, such as reactivity with acids, flammability, corrosion tendency, or how it oxidizes.

That’s why the correct choice is physical and chemical. It captures the standard division used to categorize how materials respond—either without a change in composition or through chemical transformation. The other pairings describe specific kinds of properties, not the broad two-group framework: mechanical and thermal are kinds of physical properties, structural is not a primary binary division, and electrical and optical are specific property types that fall under physical properties.