The Atomic Radius of Main-Group Elements Generally Increases Down a Group

Multiple Choice

The atomic radius of main-group elements generally increases down a group because ________.

A) effective nuclear charge increases down a group
B) effective nuclear charge decreases down a group
C) effective nuclear charge zigzags down a group
D) the principal quantum number of the valence orbitals increases
E) both effective nuclear charge increases down a group and the principal quantum number of the valence orbitals increases