Question

1. the following chart lists the atomic radii of elements in the first column of the periodic table. provided that the potassium follows the same pattern as the other elements, what is the atomic radius of potassium?

element	atomic radius in picometers (pm)
li	145
na	180
k	?
rb	235
cs	260

o 250
o 220
o 150
o 170
clear all

Explanation:

Step1: Observe the trend

As we move down the first - column (Group 1) of the periodic table from H to Cs, the atomic radius generally increases.

Step2: Analyze the given values

The atomic radius of H is 25 pm, Li is 145 pm, Na is 180 pm, Rb is 235 pm and Cs is 260 pm. The values are increasing in a somewhat regular pattern. Since K comes after Na and before Rb, its atomic radius should be greater than 180 pm and less than 235 pm. Among the given options, 220 pm is the value that fits this range.

Answer:

220