Why do copper, silver, and gold move an electron down in their configurations?

Why do copper, silver, and gold move an electron down in their configurations?

• A. To reach a half-filled d-subshell
• B. To lower energy and increase stability
• C. To maximize the number of unpaired electrons
• D. To promote complete filling of the s subshell

Answer: (B)

Electrons arrange themselves to minimize the atom’s energy, and a completely filled subshell provides unusually high stability due to how electrons interact with each other. In copper, silver, and gold, transferring one electron from the outer s orbital into the inner d subshell creates a full d subshell (d10). This extra stabilization lowers the overall energy of the atom more than keeping that electron in the s orbital, so the configuration with a single s electron and a filled d subshell is preferred. That’s why the movement happens: to lower energy and increase stability. The other ideas don’t fit because a half-filled d subshell (d5), maximizing unpaired electrons, or filling the s subshell (s2) don’t reflect the actual, more stable arrangement these elements adopt.

Electrons arrange themselves to minimize the atom’s energy, and a completely filled subshell provides unusually high stability due to how electrons interact with each other. In copper, silver, and gold, transferring one electron from the outer s orbital into the inner d subshell creates a full d subshell (d10). This extra stabilization lowers the overall energy of the atom more than keeping that electron in the s orbital, so the configuration with a single s electron and a filled d subshell is preferred.

That’s why the movement happens: to lower energy and increase stability. The other ideas don’t fit because a half-filled d subshell (d5), maximizing unpaired electrons, or filling the s subshell (s2) don’t reflect the actual, more stable arrangement these elements adopt.