Question

What simple ion does each of the following elements most commonly form? a. magnesium, $Z=12$ b. aluminum, $Z=13$ c. iodine, $Z=53$ d. calcium, $Z=20$

Short answer

a. $M{g}^{2+}$ b. $A{l}^{3+}$ c. $I^{-}$ d. $C{a}^{2+}$

Step-by-step solution

Identify the group and period of each element

First, identify the group (column) and period (row) each element belongs to in the periodic table using their atomic numbers (Z). a. Magnesium (Mg) has an atomic number of 12, and it is in Group 2 (Alkaline Earth Metals), Period 3. b. Aluminum (Al) has an atomic number of 13, and it is in Group 13, Period 3. c. Iodine (I) has an atomic number of 53, and it is in Group 17 (Halogens), Period 5. d. Calcium (Ca) has an atomic number of 20, and it is in Group 2 (Alkaline Earth Metals), Period 4.

Determine the common oxidation states

Use the group number and properties of each element to predict their common oxidation states. a. Magnesium (Group 2): Alkaline earth metals usually have an oxidation state of +2 because they have 2 valence electrons that they can lose to achieve a stable electron configuration. Therefore, the common ion formed by magnesium is $M{g}^{2+}$. b. Aluminum (Group 13): Elements in Group 13 usually have an oxidation state of +3 since they have 3 valence electrons and can lose these electrons to achieve a stable electron configuration. The common ion formed by aluminum is $A{l}^{3+}$. c. Iodine (Group 17): Halogens have an oxidation state of -1 because they have 7 valence electrons and can gain one to achieve a stable electron configuration. The common ion formed by iodine is $I^{-}$. d. Calcium (Group 2): As with magnesium, alkaline earth metals typically have an oxidation state of +2. The common ion formed by calcium is $C{a}^{2+}$.

State the simple ions for each element

Now we have the ions for each element: a. Magnesium, $Z=12$: The common ion formed is $M{g}^{2+}$. b. Aluminum, $Z=13$: The common ion formed is $A{l}^{3+}$. c. Iodine, $Z=53$: The common ion formed is $I^{-}$. d. Calcium, $Z=20$: The common ion formed is $C{a}^{2+}$.

Key concepts

Periodic Table

The periodic table is a vital tool for chemists and students alike. It organizes all known elements based on their atomic number, electron configurations, and recurring chemical properties. These elements are laid out in rows, known as periods, and columns, called groups. This arrangement helps us quickly predict the behaviors of elements, including what kinds of ions they tend to form.

• For instance, Alkali metals in Group 1 and Alkaline earth metals in Group 2 are typically metals that lose electrons to form positively charged ions.
• On the other hand, Halogens in Group 17 are non-metals that gain electrons, forming negatively charged ions.

To find an element's position on the table, we use its atomic number, which determines its place in a specific group and period.
Understanding the periodic table's layout allows us to predict the chemical behavior and reactivity of elements, aiding in the formation of ionic compounds.

Oxidation States

Oxidation states, also known as oxidation numbers, are numerical values that represent the number of electrons an atom can gain, lose or share when forming chemical compounds. These numbers help us understand how atoms interact in ionic or covalent bonds. Elements in the same group usually exhibit similar oxidation states due to having similar outer electron configurations.

• For example, elements in Group 2, such as magnesium and calcium, generally have oxidation states of +2. This is because they can lose two electrons to achieve a stable electron configuration, similar to the noble gases.
• In contrast, elements in Group 17, like iodine, often have an oxidation state of -1, as they tend to gain an electron to stabilize their electron configuration.

By understanding common oxidation states, predicting the types of ions elements will form becomes a much simpler task. This is crucial when studying ionic compounds and their properties.

Valence Electrons

Valence electrons are the electrons located in the outermost shell of an atom. They play a key role in determining how elements interact and bond chemically. Whether an atom will lose, gain, or share electrons to form ions or molecules is largely determined by these valence electrons.

• For instance, elements like magnesium in Group 2 have two valence electrons, which they can lose to form a +2 ion.
• Aluminum in Group 13 generally has three valence electrons, losing them to form a +3 ion, while iodine from Group 17 has seven valence electrons and tends to gain one more to complete its outer shell.

When atoms either lose or gain these valence electrons, they form ions, which are crucial in the formation of ionic compounds. By examining an element's valence electrons, you can often predict its chemical reactivity and the types of bonds it may form.