Give the abbreviated electron configuration for silver, 47Ag, and underline the valence electrons.
The Correct Answer and Explanation is:
Abbreviated Electron Configuration for Silver (47Ag):
[Kr] 4d10 5s1‾\text{[Kr]} \, 4d^{10} \, \underline{5s^1}[Kr]4d105s1
Explanation
Silver (Ag), with atomic number 47, is a transition metal located in group 11 of the periodic table. To understand its electron configuration, we begin by noting that electron configurations describe the distribution of electrons in an atom’s orbitals, following the Aufbau principle (electrons fill lower-energy orbitals first), Pauli exclusion principle (no two electrons in the same atom can have the same set of quantum numbers), and Hund’s rule (electrons fill orbitals singly before pairing).
The full electron configuration of silver is:
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s1 4d101s^2\, 2s^2\, 2p^6\, 3s^2\, 3p^6\, 4s^2\, 3d^{10}\, 4p^6\, 5s^1\, 4d^{10}1s22s22p63s23p64s23d104p65s14d10
To simplify, we use the noble gas shorthand. The nearest noble gas before silver is krypton (Kr), atomic number 36:
[Kr]=1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6\text{[Kr]} = 1s^2\, 2s^2\, 2p^6\, 3s^2\, 3p^6\, 4s^2\, 3d^{10}\, 4p^6[Kr]=1s22s22p63s23p64s23d104p6
So, the abbreviated configuration is:
[Kr] 4d10 5s1\text{[Kr]} \, 4d^{10} \, 5s^1[Kr]4d105s1
Valence Electrons:
For silver, the valence electrons are the outermost electrons involved in chemical bonding. These lie in the 5s and partially in the 4d orbitals. However, the 5s^1 electron is considered the most reactive and is the primary valence electron. The 4d electrons are more stable and less reactive due to being part of a filled subshell.
Thus, the valence electron(s) in silver is underlined in the configuration:
[Kr] 4d10 5s1‾\text{[Kr]} \, 4d^{10} \, \underline{5s^1}[Kr]4d105s1
This configuration is unusual because we might expect 5s^2 4d^9, but due to extra stability from a filled 4d subshell, one electron from the 5s orbital is promoted to 4d, resulting in 4d^{10} 5s^1. This is a common exception in transition metals to gain lower energy and greater stability.
