Question

list these elements in order of decreasing atomic radius: ni, pt, ds, pd → __, , , __

Explanation:

Step1: Recall atomic - radius trend

Atomic radius generally increases down a group and decreases across a period in the periodic table. Ni (Nickel) is in period 4, Pd (Palladium) is in period 5, Pt (Platinum) is in period 6, and Ds (Darmstadtium) is in period 7.

Step2: Order elements

Since the period number represents the number of electron - shells (more electron - shells mean larger atomic radius), the order of decreasing atomic radius is based on the period number.

Answer:

Ds, Pt, Pd, Ni