Identify the group number in the periodic table of X, a representative element, in each of the following ionic compounds:
a. XCl₃

Verified step by step guidance

1. Step 1: Understand the problem. The goal is to determine the group number of element X in the periodic table based on the given ionic compound XCl₃. This involves analyzing the chemical formula and the charges of the ions involved.
2. Step 2: Recall that chlorine (Cl) is a halogen and belongs to Group 17 of the periodic table. Chlorine typically forms an ion with a charge of -1 (Cl⁻) when it gains one electron.
3. Step 3: Analyze the formula XCl₃. The subscript '3' indicates that there are three chloride ions (Cl⁻) in the compound. Since each Cl⁻ ion has a charge of -1, the total negative charge contributed by the three chloride ions is -3.
4. Step 4: To balance the charges in the compound, the positive charge of the X ion must equal the total negative charge of the chloride ions. Therefore, the X ion must have a charge of +3 (X³⁺).
5. Step 5: Determine the group number of X. Representative elements in the periodic table have a group number equal to the number of valence electrons. Since X forms a +3 ion, it likely has 3 valence electrons, placing it in Group 13 of the periodic table.

Key Concepts

Representative Elements

Representative elements are found in groups 1, 2, and 13-18 of the periodic table. They are characterized by their ability to form a wide variety of compounds and exhibit predictable properties based on their group. Understanding the group number of these elements helps in predicting their ionic charges and the types of bonds they can form.

Ionic Compounds

Ionic compounds are formed when atoms transfer electrons, resulting in the formation of positively charged cations and negatively charged anions. The overall charge of the compound is neutral, and the ratio of ions is determined by their charges. In the case of XCl₃, identifying the charge of the chloride ion (Cl⁻) is essential to deduce the charge of the cation (X) and thus its group number.

Group Number and Ionic Charge

The group number of an element in the periodic table often indicates its typical ionic charge. For example, elements in group 13 typically form +3 cations, while those in group 17 form -1 anions. By analyzing the ionic compound XCl₃, one can determine the group number of X by balancing the charges, leading to insights about its chemical behavior and properties.