Question

Sulfur is to the immediate right of phosphorus in the same row in the periodic table. Which of the following statements compares the radius and number of protons of nitrogen and oxygen atoms?

Sulfur has a smaller radius and one more proton than phosphorous.
Sulfur has a smaller radius and one proton less than phosphorous.
Sulfur has a larger radius and one proton less than phosphorous.
Sulfur has a larger radius and one proton more than phosphorous.

Answer 1

it’s the 1st choice, the size of an atom decreases as you go from left to right in the period.

Answer 2

Phosphorus (P) belongs to group 15 in the periodic table with atomic number = 15

Sulfur (S) belongs to group 16 in the periodic table with atomic number = 16

Now:

Atomic number = Number of protons present in an element

Therefore:

# protons in P = 15

# protons in S = 16

Now, on moving from left to right across the periodic table, the atomic radius decreases. This is because, as the atomic number increases, the nuclear charge also increases due to which the added electron feels a stronger pull towards the nucleus.

Based on the above, S will have a smaller radius and one more proton than P

Ans:A)