Look at Selenium (Se) and Oxygen (O) on the Periodic Table which one is larger?

Answer 1

Selenium (Se) is larger than Oxygen (O) when comparing their atomic radii. Selenium is located in Group 16 and in period 4 of the periodic table, while Oxygen is in Group 16 but in period 2. As you move down a group in the periodic table, atomic size generally increases due to the addition of electron shells. Therefore, Selenium has a larger atomic radius compared to Oxygen.