Question

Which of the following has the largest atomic radius?

• A. S
• B. P
• C. As
• D. SE

Answer 1

Answer: (C)

As

• Atomic radius decreases from left to right within a period. This is caused by the increase in the number of protons and electrons across a period. One proton has a greater effect than one electron; thus, electrons are pulled towards the nucleus, resulting in a smaller radius.
  
• The number of energy levels increases as you move down a group as the number of electrons increases. Each subsequent energy level is further from the nucleus than the last. Therefore, the atomic radius increases as the group and energy levels increase.
  
• Hence among the given options $As$ is having largest atomic radius.