Question

Each set of lettered choices below refers to the numbered statements immediately following it. Select the one lettered choice that best fits each statement. A choice may be used once more, more than once, or not at all in each set. Which one has the largest radius?

A. Cs
B. Ag
C. Pb
D. Br
E. Se

Answer 1

Comparing the elements lead (Pb) and selenium (Se) based on periodic table trends, lead (Pb) has the larger atomic radius. This is because Pb is further down its group on the periodic table, indicating it has more electron shells.

Step-by-step explanation:

To determine which element has the largest atomic radius between lead (Pb) and selenium (Se), we can refer to the periodic table trends. The atomic radius of an element tends to increase as we move down a group because additional electron shells are added, making the atom larger. Conversely, atomic radius tends to decrease as we move from left to right across a period, due to the increase in positive charge of the nucleus which attracts the electrons more strongly and shrinks the radius.

Lead (Pb) is located in group 14 and period 6, while selenium (Se) is in group 16 and period 4. Since Pb is further down in the same group than where Se is located (not accounting for the lanthanide and actinide series), it will have more electron shells and therefore, generally a larger atomic radius than Se. Hence, Pb has the larger atomic radius.