Four elements are designated as P, Q, R, and S with atomic numbers 8, 12, 13, and 19 respectively. Which of the following represents the correct increasing order of their metallic character?

Step-by-step solution

The elements are identified by their atomic numbers: P ( Z = 8 ) is Oxygen (Group 16, Period 2). Q ( Z = 12 ) is Magnesium (Group 2, Period 3). R ( Z = 13 ) is Aluminium (Group 13, Period 3). S ( Z = 19 ) is Potassium (Group 1, Period 4). Metallic character decreases across a period from left to right and increases down a group. Oxygen is a non-metal and has the least metallic character. Between Magnesium and Aluminium (same period), Magnesium is more metallic because it is further to the left in the periodic table