Question

Apply lon \(X\) has a charge of \(2+,\) and ion \(Y\) has a charge of \(1-.\) Write the formula unit of the compound formed from the ions.

Short answer

The formula unit of the compound formed from ion X with a charge of \(2+\) and ion Y with a charge of \(1-\) is XYP2.

Step-by-step solution

1. Determine the charges of the ions

We are given that ion X has a charge of 2+ and ion Y has a charge of 1-.

2. Determine the least common multiple of the charges

In order for the compound to be electrically neutral, we need to find the least common multiple (LCM) of the magnitudes of these charges. In this case, the charges are 2 and 1. The LCM of 2 and 1 is 2.

3. Calculate the number of each ion to balance the charges

To obtain the LCM of 2, we need 1 of ion X with a charge of 2+ and 2 of ion Y with a charge of 1-. This will result in an overall neutral compound.

4. Write the formula unit

The formula unit for the resulting compound will be written as XYP2, where 1 of ion X (with a charge of 2+) is combined with 2 of ion Y (with a charge of 1-) to give a neutral compound. So, the formula unit of the compound formed from the ions X and Y is XYP2.

Key concepts

Ion Charges

Understanding ion charges is critical when dealing with the formation of ionic compounds in chemistry. An ion is an atom or molecule that has an electrical charge due to the loss or gain of one or more electrons. When an atom loses electrons, it becomes a positively charged ion, or cation, and when it gains electrons, it becomes a negatively charged ion, or anion.

For example, in our exercise, ion X has a charge of 2+ (cation), and ion Y has a charge of 1- (anion). The magnitude of the charge not only determines the electric potential of the ion but also its ability to combine with ions of opposite charges to form neutral compounds. An understanding of ion charges is essential when trying to decipher the stoichiometry of the resulting ionic compound, to ensure that the number of positive and negative charges balance out to produce a neutral species.

Least Common Multiple in Chemistry

In chemistry, the least common multiple (LCM) plays a significant role in determining the ratios of ions that will combine to form an electrically neutral compound. The charges of the ions often need to be balanced by multiplying them with appropriate integers to achieve a neutral overall charge.

The exercise demonstrates this by requiring us to calculate the LCM of the ion charges to determine how many of each ion are needed. Since ion X has a charge of 2+, and ion Y has a charge of 1-, the LCM is 2. This means that for every one ion X, two ions Y are required to balance the charge. The LCM, thus, gives us a straightforward method to ascertain the ratios in which different ions will combine to form a compound, ensuring that total positive charges equal total negative charges, effectively leading to an electrically neutral entity.

Chemical Formula Writing

Writing chemical formulas is an essential skill in chemistry that conveys a wealth of information about a substance. The chemical formula represents the types and numbers of atoms in a molecule or compound. When writing the formula for an ionic compound, it's important to understand that the compound must be electrically neutral, meaning the total positive charges must balance the total negative charges.

In the given problem, after balancing the charge with the LCM, we determine the correct formula unit for the compound formed by ions X and Y to be XYP2. This formula indicates that there's one atom of ion X for every two atoms of ion Y. When writing chemical formulas, it is imperative not to include the ionic charges in the final formula but to ensure that the subscript numbers of the ions present reflect the ratios needed for charge neutrality.