The third transition series metals are shown below.
-Which has the largest atomic radius?
A)La
B)W
C)Os
D)Hg

Question

The third transition series metals are shown below. 
-Which has the largest atomic radius?
A)La 
B)W 
C)Os 
D)Hg

Quizplus · Accepted Answer

La (Lanthanum) has the largest atomic radius because it is located at the beginning of the third transition series and therefore has the least amount of effective nuclear charge compared to the other elements in the series. As you move from left to right across a series, the effective nuclear charge increases, causing the atomic radius to decrease. Therefore, W (Tungsten), Os (Osmium), and Hg (Mercury) all have smaller atomic radii than La.

The Third Transition Series Metals Are Shown Below