Silver ion (Ag+) is a univalent cation with a unit positive charge formed by the loss of only one electron in the outermost layer of silver atom.
Silver atom (Ag) is the element of Group Ⅰ B in the fifth cycle
So there are five electron layers outside the nucleus, and the arrangement of electrons outside the nucleus is 2, 8, 18, 18, 1. There is only one electron in the outermost layer and 18 electrons in the secondary layer. Therefore, when the outermost electron is lost, it becomes silver ion (Ag+). At this time, the secondary outer layer becomes the outermost layer of silver ion, so there are 18 electrons in the outermost layer of silver ion.