Question

Copper, silver, and gold are transition metals that fall into the same group on the periodic table. From the following list, identify those metals that cannot be oxidized by cations of all three of these metals from group 11.
Select all that apply:
Nickel, magnesium, tin, zinc, platinum, mercury, lead, manganese, lithium, iron, barium, aluminum, potassium, cobalt.

Answer 1

The correct answer is Platinum.

The metals which are not oxidized by an ion, they should be less reactive than silver, gold, and copper is platinum.
All group 11 elements are relatively corrosion-resistance metals and they are inert.
They have low electrical resistivity and are used for wiring. Copper, Silver, and gold are the most thermally conductive element and most light reflecting.

Answer 2

For a metal to not be oxidized by an ion, it has to be less reactive than it. The only metal in the list less reactive than Copper, Silver and Gold is Platinum. You may check a reactivity series for reference.