Question

Use the periodic table to predict an ionic charge for each of the following metal ions: (a) Na ion (b) Ba ion (c) Ga ion (d) Sn ion

Short answer

(a) +1, (b) +2, (c) +3, (d) +2 or +4

Step-by-step solution

Locate the Element on the Periodic Table

To predict the ionic charge of a given metal ion, first locate the element on the periodic table. For instance, Sodium (Na) is in Group 1, Barium (Ba) is in Group 2, Gallium (Ga) is in Group 13, and Tin (Sn) is in Group 14.

Determine the Common Ionic Charge Based on Group

The group number often indicates the common oxidation state for an element. Elements in Group 1 (like Na) typically have a +1 charge. Those in Group 2 (like Ba) have a +2 charge. For Group 13 elements like Ga, the common charge is +3. Tin (Sn), in Group 14, can exhibit multiple charges, but the common oxidation states are +2 and +4.

Note the Charge

According to the group and its typical behavior: (a) Na ion has a charge of +1, (b) Ba ion has a charge of +2, (c) Ga ion has a charge of +3, and (d) Sn ion can have a charge of either +2 or +4.

Key concepts

Periodic Table

The periodic table is a powerful tool in chemistry. It organizes elements based on their atomic number, electron configuration, and recurring chemical properties. This organization helps us to predict the behavior of elements, including their ionic charges.
When you look at the periodic table, you'll notice that elements are arranged in groups (or columns). These groups tell us a lot about how elements behave. This is because elements in the same group have similar valence electron configurations. Valence electrons are the outermost electrons involved in bonding.

• Elements in Group 1 typically lose one electron to form a +1 ion.
• Group 2 elements lose two electrons, resulting in a +2 ion.
• Elements in Groups 13 might form a +3 ion.
• As we move to the right and down the table, the behavior of elements becomes more complex. This complexity is due to the increasing number of valence electrons.

The periodic table's arrangement is more than just a list; it provides insights into electron affinities and electronegativities crucial for predicting chemical behavior.

Metal Ions

Metal ions are atoms that have lost one or more electrons. This loss results in a positive charge due to more protons than electrons in the atom. Metals are typically found on the left side of the periodic table.
Metals usually form positive ions because they prefer to lose electrons. This tendency allows them to achieve a more stable electron configuration, often resembling the nearest noble gas.

• Sodium (Na), a metal in Group 1, loses one electron to form its ionic state: Na⁺.
• Barium (Ba), found in Group 2, commonly loses two electrons to become Ba²⁺.
• Gallium (Ga) from Group 13 often loses three electrons, resulting in Ga³⁺.
• Tin (Sn) is a metal that can form multiple ions, such as Sn²⁺ or Sn⁴⁺, depending on conditions.

Metals lose electrons because it allows them to have filled energy levels like those of the stable noble gases. Understanding this behavior is key to predicting how metallic elements will form ions.

Oxidation States

Oxidation states, also known as oxidation numbers, represent the degree of oxidation of an element in a chemical compound. They provide indications about the number of electrons an element might gain, lose, or share in a bond.
For metals, their oxidation state often aligns with the number of electrons they lose to achieve stable electron configurations. The oxidation state corresponds with the common ionic charge based on their group position.

• Group 1 metals, like sodium (Na), have an oxidation state of +1.
• Group 2 metals, such as barium (Ba), typically show a +2 oxidation state.
• Group 13 metals, such as gallium (Ga), often exhibit a +3 oxidation state.
• Tin (Sn) is unique as it can have two typical oxidation states: +2 and +4.

Understanding oxidation states is critical because it helps predict how elements will interact in compounds. They guide reactions, allowing us to balance chemical equations and anticipate the products formed. This knowledge is essential for students and chemists alike.