Gamma rays differ from alpha and beta rays in that they: MCQ with Answer and Explanation

Explanation:
Group 18 elements are noble gases: helium, neon, argon, krypton, xenon, radon. They have completely filled valence shells, making them chemically inert (though xenon can form compounds). Nitrogen is Group 15, Oxygen Group 16, Hydrogen is unique (Group 1).

Explanation:
Hydrochloric acid (HCl) dissociates completely in water, making it a strong acid. Acetic acid (CH₃COOH), carbonic acid (H₂CO₃), and citric acid are weak acids—they partially ionize. Other strong acids: H₂SO₄ (first dissociation), HNO₃, HBr, HI, HClO₄. Strong acids have very large Ka values. pH of 0.1 M HCl is about 1.

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.