Step 1: Understand what valency means. Valency is the number of electrons an atom needs to gain, lose, or share to complete its outer shell.
Step 2: Look at the atomic structure of oxygen. Oxygen has 8 electrons in total.
Step 3: Determine how many electrons are in the outer shell of oxygen. The outer shell can hold a maximum of 8 electrons, but oxygen has only 6 in its outer shell.
Step 4: Calculate how many more electrons oxygen needs to complete its outer shell. Since it has 6 electrons, it needs 2 more to reach 8.
Step 5: Conclude that the valency of oxygen is 2 because it needs 2 electrons to fill its outer shell.
