Which property of matter remains constant regardless of changes in its state?

Correct Answer: A

Rationale: The correct answer is 'Mass.' Mass is a measure of the amount of matter in an object and remains constant regardless of changes in its state. When matter changes its state (solid, liquid, gas), its mass remains the same. On the other hand, volume can change with the shape the matter takes, density changes as the mass is distributed differently, and weight can vary with the gravitational pull. Therefore, mass is the property that remains constant irrespective of the state of matter, making it the correct choice in this scenario.

Correct Answer: A

Rationale: Malleability is the correct answer as it is the property of a substance that allows it to be hammered or pressed into thin sheets without breaking. This property is crucial for materials like metals that need to be shaped without breaking. Ductility, on the other hand, refers to the ability of a substance to be drawn into thin wires, not hammered into sheets. Viscosity is a measure of a fluid's resistance to flow, indicating its thickness or thinness, and is unrelated to the ability to be hammered. Conductivity, on the other hand, refers to a substance's ability to conduct electricity or heat, which is not related to its ability to be hammered or pressed into thin sheets.

Correct Answer: D

Rationale: Volume is the property of matter that measures the amount of space occupied by an object. Mass refers to the amount of matter in an object, weight is the force of gravity acting on an object, and density is the mass of an object per unit volume. Volume specifically quantifies the space occupied by an object, making it the correct answer in this context.

Correct Answer: A

Rationale: The electron configuration of an atom refers to the arrangement of electrons in the atom's orbitals. This arrangement determines the atom's chemical properties and behavior. The number of protons in an atom's nucleus (option B) is known as the atomic number, which defines the element. The number of neutrons in an atom's nucleus (option C) contributes to the atom's mass number. The number of electrons in an atom's valence shell (option D) is important for understanding the atom's reactivity and bonding behavior, but the electron configuration specifically refers to how electrons are distributed among the different orbitals in an atom.

Correct Answer: B

Rationale: A concave lens is thinner at the center than at the edges, causing light rays to diverge when passing through it. This type of lens is also known as a diverging lens because it causes light rays to spread out. Concave lenses are used in various optical devices to correct vision problems and in scientific instruments to diverge light rays for specific purposes. The other choices are incorrect. A convex lens is thicker at the center and converges light rays, while a plano-convex lens has one flat surface and one convex surface, converging light. Diverging lens is a general term that can refer to concave or plano-concave lenses, but in this context, the specific type being referred to is a concave lens.