Which of the following correctly arranges the atoms and ions in order of increasing atomic radius: Se, Se2-, Te2-?

Arrange these elements in order of increasing atomic radius: F, S, Si, Ge, Ca, Rb.

Arrange these elements in order of decreasing atomic radius: Cs, Pb, Sb, Se, S.

Explain why atomic radius decreases as you move to the right across a period for main-group elements but not for transition elements.

Explain why vanadium (radius = 134 pm) and copper (radius = 128 pm) have nearly identical atomic radii, even though the atomic number of copper is about 25% higher than that of vanadium. Predict the relative densities of these two metals. Look up the densities in a reference book, periodic table, or on the Internet to check if your predictions are correct.

Which atom in each group has the smallest atomic radius? Na, Si, Cl; Be, Mg, Ca?

Which of the following statements correctly describes the trend in atomic radius across a period in the periodic table?