Silver has 47 electrons arranged as 2, 8, 18, 18, 1 across 5 shells, which is why it sits in period 5.
Start from the previous noble gas core, written in square brackets, then add the remaining electrons in filling order. For silver that gives [Kr] 4d10 5s1.
Exception to the Aufbau rule. Filling orbitals in order would give 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d9, but the real configuration is 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s1 because a completely filled 4d¹⁰ is extra stable, just like copper above it.
| Atomic number | 47 |
| Symbol | Ag |
| Atomic mass | 107.87 u |
| Group | 11 |
| Period | 5 |
| Block | d-block |
| Category | Transition metal |
| Element | Configuration |
|---|---|
| Copper | [Ar] 3d10 4s1 |
| Gold | [Xe] 4f14 5d10 6s1 |
| Roentgenium | [Rn] 5f14 6d9 7s2 |