Question

Write the formula for and indicate the charge on each of the following ions: a. sodium ion b. aluminum ion c. chloride ion d. nitride ion e. iron(II) ion f. iron(III) ion

Short answer

a. \(\text{Na}^+\), b. \(\text{Al}^{3+}\), c. \(\text{Cl}^-\), d. \(\text{N}^{3-}\), e. \(\text{Fe}^{2+}\), f. \(\text{Fe}^{3+}\).

Step-by-step solution

Sodium Ion

Sodium is a Group 1 element, hence it loses one electron to form a cation with a +1 charge. The formula for the sodium ion is \(\text{Na}^+\).

Aluminum Ion

Aluminum is a Group 13 element, hence it loses three electrons to form a cation with a +3 charge. The formula for the aluminum ion is \(\text{Al}^{3+}\).

Chloride Ion

Chlorine is a Group 17 element, hence it gains one electron to form an anion with a -1 charge. The formula for the chloride ion is \(\text{Cl}^-\).

Nitride Ion

Nitrogen is a Group 15 element, hence it gains three electrons to form an anion with a -3 charge. The formula for the nitride ion is \(\text{N}^{3-}\).

Iron(II) Ion

Iron(II) indicates iron has a +2 oxidation state. The formula for the iron(II) ion is \(\text{Fe}^{2+}\).

Iron(III) Ion

Iron(III) indicates iron has a +3 oxidation state. The formula for the iron(III) ion is \(\text{Fe}^{3+}\).

Key concepts

sodium ion

When talking about sodium ions, we need to consider its position on the periodic table. Sodium is a Group 1 element. Elements in this group typically lose one electron to achieve a stable electron configuration. This makes them positively charged cations.

For sodium specifically, losing one electron results in a charge of +1. Thus, the formula for the sodium ion is written as \(\text{Na}^+\). It’s crucial to understand that losing an electron makes the ion smaller and positively charged.

aluminum ion

Aluminum is found in Group 13 of the periodic table. Elements in this group often lose three electrons to form cations with a +3 charge. This is due to aluminum having three electrons in its outer shell that it 'wants' to lose to achieve stability.

Therefore, the formula for an aluminum ion is \(\text{Al}^{3+}\). Knowing these patterns for specific groups can help you predict the charges and formulas of these ions easily.

chloride ion

Chlorine belongs to Group 17, which is also known as the halogens. These elements tend to gain one electron to complete their outer shell, which makes them negatively charged anions.

For chlorine, gaining one electron results in a charge of -1. Thus, the chloride ion has a formula of \(\text{Cl}^-\). Remember, gaining an electron increases the size of the ion and gives it a negative charge.

nitride ion

Nitrogen is part of Group 15 on the periodic table. Elements in this group typically gain three electrons to achieve a full outer shell, resulting in a -3 charge.

In the case of nitrogen, this means the nitride ion is represented with the formula \(\text{N}^{3-}\). Understanding electron configurations can significantly help in predicting these charges.

iron(II) ion

The iron(II) ion, often referred to as ferrous ion, indicates that iron is in the +2 oxidation state. Unlike the earlier elements which follow a predictable pattern in their groups, transition metals like iron can have multiple oxidation states.

Thus, the formula for the iron(II) ion is written as \(\text{Fe}^{2+}\). This information is critical for understanding how iron behaves in various chemical reactions.

iron(III) ion

Iron can also have a +3 oxidation state, which is referred to as the iron(III) or ferric ion. This happens when iron loses three electrons.

Consequently, the formula for the iron(III) ion is \(\text{Fe}^{3+}\). Recognizing these different oxidation states is important for predicting how iron will interact in both redox reactions and ionic compounds.