Aluminum arsenide has the formula Alas. a. What is the charge on the aluminum ion? b. What is the charge on the arsenic ion? c. Show that the charges on the ions add up to zero. d. What is the total number of valence electrons in all the atoms in Alas?
The correct answer and explanation is :
Let’s break down the answers to each part of the question, and then I’ll provide an explanation.
a. What is the charge on the aluminum ion?
Aluminum (Al) is in Group 13 of the periodic table. Elements in this group typically form ions with a charge of +3. This is because aluminum has three valence electrons, and it tends to lose these electrons to achieve a stable electron configuration. Thus, the charge on the aluminum ion in aluminum arsenide (AlAs) is +3.
b. What is the charge on the arsenic ion?
Arsenic (As) is in Group 15 of the periodic table. Elements in this group typically form ions with a charge of -3. Arsenic has five valence electrons, and it tends to gain three electrons to achieve a stable electron configuration. Therefore, the charge on the arsenic ion in aluminum arsenide is -3.
c. Show that the charges on the ions add up to zero.
The formula for aluminum arsenide is AlAs, which means there is one aluminum ion (Al³⁺) and one arsenic ion (As³⁻). The total charge on the compound is the sum of the charges of the ions:
- Aluminum ion (Al³⁺) has a charge of +3.
- Arsenic ion (As³⁻) has a charge of -3.
When we add the charges together:
+3 + (-3) = 0.
This shows that the charges on the ions add up to zero, which is a characteristic feature of neutral compounds.
d. What is the total number of valence electrons in all the atoms in AlAs?
To calculate the total number of valence electrons, we look at the valence electrons for each element:
- Aluminum (Al): Aluminum is in Group 13, so it has 3 valence electrons.
- Arsenic (As): Arsenic is in Group 15, so it has 5 valence electrons.
Since there is one aluminum atom and one arsenic atom in AlAs, the total number of valence electrons is:
3 (from Al) + 5 (from As) = 8 valence electrons.
Explanation:
In aluminum arsenide (AlAs), aluminum has a charge of +3 and arsenic has a charge of -3. The compound is neutral, so the sum of the charges on the ions is zero. The number of valence electrons is calculated by adding the valence electrons of each atom: aluminum contributes 3 valence electrons, and arsenic contributes 5 valence electrons, for a total of 8 valence electrons. These valence electrons are involved in bonding to form a stable ionic compound where the charges cancel each other out.