Answer:
most similar to potassium = rubidium
least similar to potassium = thallium
Explanation:
The density of an element is the number of particles per unit volume. To determine the element with the most probable density and the least density, we need to know their density values.
For potassium, density = 0.862 g/cm³
Density of lead = 11.35 g/cm³
Density of rubidium = 1.63 g/cm³
Density of thallium = 11.85 g/cm³
Density of xenon = 5.9 g.cm³
So from their density values, the density that has the most similar density to potassium is rubidium.
The element that is least similar to potassium is thallium.