place the following atoms in order of increasing atomic radius (1 = smallest, 4 = largest): n, p, sb, bi.

Explanation:

Step1: Recall atomic - radius trend

Atomic radius increases down a group and decreases across a period. N, P, Sb, and Bi are all in Group 15.

Step2: Identify period number

N is in Period 2, P is in Period 3, Sb is in Period 5, and Bi is in Period 6.

Step3: Order by atomic radius

As we go down the group, the atomic radius increases. So the order of increasing atomic radius is N < P < Sb < Bi.

Answer:

N = 1, P = 2, Sb = 3, Bi = 4