To determine which elements can likely form ions with multiple charges based on their electron configurations, let's analyze the electron configurations provided for each element:
1. Zinc: [Ar] 3d^{10} 4s^2
- Zinc has a fully filled d-subshell (3d^{10}) and typically forms a +2 ion by losing its two 4s electrons. It's relatively stable with a +2 oxidation state and does not commonly form ions with other charges.
2. Iron: [Ar] 3d^6 4s^2
- Iron can lose electrons from both the 4s and 3d subshells, leading to multiple oxidation states. Iron commonly forms +2 (ferrous, by losing two 4s electrons) and +3 (ferric, by losing two 4s electrons and one 3d electron) ions.
3. Sodium: [Ne] 3s^1
- Sodium typically forms a +1 ion by losing its single 3s electron. Sodium does not commonly form ions with other oxidation states because losing more than one electron would require significantly more energy.
4. Cobalt: [Ar] 3d^7 4s^2
- Cobalt can lose both 4s and 3d electrons, resulting in multiple oxidation states. Cobalt commonly forms +2 (by losing two 4s electrons) and +3 (by losing two 4s electrons and one 3d electron) ions.
5. Silver: [Kr] 4d^{10} 5s^1
- Silver commonly forms a +1 ion by losing its single 5s electron. Though silver's electron configuration suggests possible +2 states, it primarily forms +1 ions in practice.
Based on these electron configurations, the elements that are likely to form ions with multiple charges are iron and cobalt. Therefore, the correct answers are:
- Iron
- Cobalt
Thus, the indices of the elements that likely form ions with multiple charges based on their electron configurations are:
[tex]\[2, 4\][/tex]
