What is the general outer electronic configuration of the coinage metals (Group 11)?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → (n − 1)d10 ns1
The coinage metals are the Group 11 elements Cu, Ag and Au. A completely filled d subshell is extra stable, so one ns electron moves into the (n − 1)d subshell: Cu is 3d104s1 (not 3d94s2), Ag is 4d105s1 and Au is 5d106s1.
NCERT (2026-27 edition):
4.2 Electronic Configurations of the d-Block Elements – “… Furthermore, half and completely filled sets of orbitals are relatively more stable. A consequence of this factor is reflected in the electronic configurations of Cr and Cu in the 3d series. … Similarly in case of Cu, the configuration is 3d104s1 and not 3d94s2. The ground state electronic configurations of the outer orbitals of transition elements are given in Table 4.1.”
Table 4.1: Electronic Configurations of outer orbitals of the Transition Elements (ground state)
