Petroleum is separated into fractions by: MCQ with Answer and Explanation

Explanation:
The diagonal relationship occurs when elements in the second period resemble elements in the third period of the next group due to similar ionic sizes and charge-to-radius ratios (polarizing power). Li-Mg, Be-Al, and B-Si are all classic examples of this phenomenon.

Explanation:
The periodic table has 7 horizontal rows called periods. Elements in the same period have the same number of electron shells. Properties change gradually across a period. Groups are vertical columns (18), where elements have similar valence electron configurations and thus similar chemical properties. Families are informal group names (e.g., halogens). Blocks (s, p, d, f) are based on the orbital in which the last electron enters.

Explanation:
Aqua regia (royal water) is a 3:1 mixture of concentrated HCl and HNO₃. It can dissolve noble metals gold and platinum by forming complex ions. Freshly prepared, it is a fuming yellow liquid. Used in etching and cleaning.