Which element corresponds to the electron configuration [Kr] 5s^2 4d^9?

The provided electron configuration [Kr] 5s^2 4d^9 indicates that the element has a total of 47 electrons. The notation [Kr] represents the electron configuration of the noble gas Krypton, which accounts for the first 36 electrons. Adding the 5s^2 (which contributes 2 electrons) and 4d^9 (which contributes 9 electrons) gives us a total of 36 + 2 + 9 = 47 electrons overall.

The element with 47 electrons is Silver (Ag), which is located in group 11 of the periodic table. Silver's electron configuration can also be expressed in a full notation as [Kr] 5s^2 4d^9, where the partially filled 4d subshell is characteristic of transition metals, particularly those in group 11.

This aligns directly with the choice of Silver as the answer, as it confirms the accurate electron configuration corresponding to the element that has 47 electrons.