🧪 Chemistry

Explanation: The chemical symbol for gold is Au, derived from the Latin word aurum. Gold's atomic number is 79.

Explanation: Aluminium is the most abundant metal in Earth's crust, making up about 8% of its total mass. It is found mainly as bauxite ore.

Explanation: Common salt (sodium chloride) has the chemical formula NaCl, consisting of one sodium (Na) and one chlorine (Cl) atom held together by an ionic bond.

Explanation: Pure water has a pH of 7, which is neutral. pH below 7 is acidic and above 7 is basic/alkaline.

Explanation: Hydrogen has atomic number 1, meaning it has one proton. It is the lightest and most abundant element in the universe.