A catalyst works by: MCQ with Answer and Explanation

Explanation:
Rutherford bombarded a thin gold foil with alpha particles. Most passed through, but some were deflected, leading to the nuclear model.

Explanation:
Propane is an alkane with three carbon atoms: CH₃CH₂CH₃, formula C₃H₈. Methane: CH₄, Ethane: C₂H₆, Butane: C₄H₁₀. Propane is a component of LPG. Alkanes follow CnH₂n+2. For n=3, H=8. Propane is a gas at room temperature, liquefied under pressure. It is used as fuel for heating and cooking.

Explanation:
Atomic number (Z) = Mass number (A) – Number of neutrons (N) = 39 – 20 = 19. This is potassium (K). Number of protons equals atomic number. In a neutral atom, electrons also equal Z.