Problem 96 - Chemistry Matter and Change

Question

What is the charge of an ion formed from the following families? (Chapter 7) a. alkali metals b. alkaline earth metals c. halogens

Step-by-Step Solution

Answer

a. Alkali metals form ions with a charge of \(+1\) b. Alkaline earth metals form ions with a charge of \(+2\) c. Halogens form ions with a charge of \(-1\)

Step 1: Identify the families in the periodic table

Alkali metals are found in Group 1 (the first column) of the periodic table. Alkaline earth metals are in Group 2 (the second column), and halogens are in Group 17 (the second to last column).

Step 2: Determine the ion charges for alkali metals

Alkali metals have one valence electron (an electron in their outermost shell) and tend to lose one electron during chemical reactions to achieve a stable electron configuration. When they lose this electron, they form a positively charged ion with a charge of +1.

Step 3: Determine the ion charges for alkaline earth metals

Alkaline earth metals have two valence electrons. They tend to lose both of these electrons in order to achieve a stable electron configuration. When they lose these electrons, they form a positively charged ion with a charge of +2.

Step 4: Determine the ion charges for halogens

Halogens have seven valence electrons and tend to gain one electron during chemical reactions to complete their outer electron shell. When they gain this electron, they form a negatively charged ion with a charge of -1. Now that we have determined the ion charges for each family, we can provide our final answers: a. Alkali metals form ions with a charge of +1 b. Alkaline earth metals form ions with a charge of +2 c. Halogens form ions with a charge of -1

Key Concepts

Alkali Metals

Alkali metals are a group of elements located in the first column, or Group 1, of the periodic table. These metals are characterized by having a single valence electron. This lone valence electron plays a crucial role in their chemical behavior. Due to this, alkali metals are highly reactive, more so than other metal groups. One explanation for this reactivity is the tendency of alkali metals to lose their single valence electron easily. By doing this, they achieve a stable electronic configuration similar to noble gases.

• When they lose their valence electron, alkali metals form positively charged ions.
• These ions possess a charge of +1, which occurs because there is now one more proton than electrons in the atom.

Spanning from Lithium (Li) to Francium (Fr), alkali metals are widely known for their applications in various industries, such as batteries and medicine.

Alkaline Earth Metals

Alkaline earth metals are another critical group of elements, located in Group 2 of the periodic table. They possess two valence electrons, which is key to understanding their behavior in chemical reactions. These metals tend to be less reactive than alkali metals but still quite reactive, especially when undergoing oxidation.

• Alkaline earth metals lose both of their valence electrons to achieve a stable electron configuration.
• When they lose these two electrons, they form ions with a +2 charge.

This process of electron loss is similar to alkali metals but involves two electrons instead of one, giving rise to higher positive charges for the ions. Elements like Magnesium (Mg) and Calcium (Ca) belong to this group and are essential in various applications, from construction to health supplements.

Halogens

Halogens are a family of nonmetals found in Group 17 of the periodic table. Distinguished by having seven valence electrons, halogens are unique in their high reactivity, particularly with metals. Their reactivity is primarily driven by their need to gain only one more electron to complete their valence shell.

• In chemical reactions, halogens typically gain an electron to form stable configurations.
• Upon gaining this electron, halogens produce anions with a net charge of -1.

This single gained electron balances the extra positive charge of protons over electrons, resulting in overall negative ion formation. The halogen group includes elements such as Fluorine (F), Chlorine (Cl), and Iodine (I), extensively utilized in disinfection and bleaching processes.

Valence Electrons

Valence electrons are the electrons located in the outermost electron shell of an atom. These electrons are paramount when considering an element's ability to bond and react with other elements. The number of valence electrons can dictate the chemical properties and capabilities of the elements.

• These electrons determine how an element will react and with which it may bond.
• Elements in the same group of the periodic table have the same number of valence electrons.

The shared valence count within groups explains the similarities in chemical behavior among family members, such as all Group 1 elements having one valence electron. Mastery of valence electron concepts allows scientists and chemists to predict reaction patterns across the entire table effectively.

Periodic Table Groups

The periodic table consists of columns known as groups or families. Each group contains elements that exhibit similar chemical behaviors due to having the same number of valence electrons. Therefore, elements in the same group often display comparable properties and reactivity patterns.

• Groups are vertical columns, and there are 18 numbered groups in the periodic table.
• The properties of elements within a group are remarkably consistent due to their electron configuration similarities.

Understanding the organization into groups helps streamline the study of chemical behaviors and interactions. Knowledge of these groups aids in identifying the potential reactions and uses of elements, allowing scientists to predict the formation of ions and compounds effortlessly.