Please can somebody teach me resultant vectors

Achlorine atom has 17 protons and 18 neutrons. what is its mass number? what is its atomic number?

Nacidified solution was electrolyzed using copper electrodes. a constant current of 1.18 a caused the anode to lose 0.584 g after 1.52 ✕ 103 s. given that the charge of an electron is 1.6022 ✕ 10−19 c, calculate avogadro's number. assume that copper is oxidized to cu2+ ions.

Distinguish between linear momentum and angular momentum