Question

periodic trends classwork - 12/04/2025
question 3. identify the element with the greatest atomic radius.
a) phosphorus (p), potassium (k), chlorine (cl)
b) oxygen (o), fluorine (f), strontium (sr)

Explanation:

Part a)

Step1: Recall atomic radius trends

Atomic radius increases down a group and decreases across a period (left to right). P, K, Cl are in the same period (period 3).

Step2: Determine position in period

In period 3, K is on the left, P in the middle, Cl on the right. So K has the largest atomic radius among P, K, Cl.

Step1: Recall atomic radius trends

Atomic radius increases down a group and decreases across a period (left to right). O, F are in period 2; Sr is in period 5.

Step2: Compare periods and groups

Sr is in a lower period (period 5) than O (period 2) and F (period 2). Down a group, radius increases. So Sr has the largest atomic radius among O, F, Sr.

Answer:

Potassium (K)

Part b)