Give the formula and charge of the oxyanion in each of the following compounds:
(a) Potassium sulfite
(b) Sodium perchlorate
(c) Lithium phosphite
(d) Magnesium hypochlorite
(a) Potassium sulfite 2- (K2SO3)
(b) Sodium perchlorate 1- (NaClO4)
(c) Lithium phosphite 3- (Li3PO4)
(d) Magnesium hypochlorite 1- [Mg(ClO)2]
To determine the formula and charge of the oxyanion in each of the given compounds, we need to know the charges of the cations (Potassium, Sodium, Lithium, Magnesium) and the names of the oxyanions (sulfite, perchlorate, phosphite, hypochlorite).
(a) Potassium sulfite:
The cation, potassium (K+), has a charge of +1 since it is an alkali metal. The anion, sulfite (SO3^2-), has a charge of -2. To balance the charges, we need two potassium cations for every sulfite anion. Therefore, the formula for potassium sulfite is K2SO3, and the oxyanion is sulfite (SO3^2-).
(b) Sodium perchlorate:
The cation, sodium (Na+), has a charge of +1. The anion, perchlorate (ClO4^-), has a charge of -1. Again, we need only one sodium cation to balance the charge of one perchlorate anion. Therefore, the formula for sodium perchlorate is NaClO4, and the oxyanion is perchlorate (ClO4^-).
(c) Lithium phosphite:
The cation, lithium (Li+), has a charge of +1. The anion, phosphite (PO3^3-), has a charge of -3. To balance the charges, we need three lithium cations for every phosphite anion. Thus, the formula for lithium phosphite is Li3PO3, and the oxyanion is phosphite (PO3^3-).
(d) Magnesium hypochlorite:
The cation, magnesium (Mg^2+), has a charge of +2. The anion, hypochlorite (ClO^-), has a charge of -1. To balance the charges, we need two magnesium cations for every hypochlorite anion. Hence, the formula for magnesium hypochlorite is Mg(ClO)2, and the oxyanion is hypochlorite (ClO^-).
Remember, the charges of common ions can be found using the periodic table and considering their position and group in the table. Additionally, the names of oxyanions can sometimes provide clues to their charges based on their suffixes.
(a) Potassium sulfite
- The formula for potassium sulfite can be determined by balancing the charges of the potassium ion and the sulfite ion.
- Potassium is a group 1A element, so it has a charge of +1 (K+).
- Sulfite (SO3) has a charge of -2 based on the combination of its constituent elements.
- Since the overall charge should be neutral, the formula for potassium sulfite is K2SO3.
(b) Sodium perchlorate
- The formula for sodium perchlorate can be determined by balancing the charges of the sodium ion and the perchlorate ion.
- Sodium is a group 1A element, so it has a charge of +1 (Na+).
- Perchlorate (ClO4) has a charge of -1 based on the combination of its constituent elements.
- Since the overall charge should be neutral, the formula for sodium perchlorate is NaClO4.
(c) Lithium phosphite
- The formula for lithium phosphite can be determined by balancing the charges of the lithium ion and the phosphite ion.
- Lithium is a group 1A element, so it has a charge of +1 (Li+).
- Phosphite (PO3) has a charge of -3 based on the combination of its constituent elements.
- Since the overall charge should be neutral, the formula for lithium phosphite is Li3PO3.
(d) Magnesium hypochlorite
- The formula for magnesium hypochlorite can be determined by balancing the charges of the magnesium ion and the hypochlorite ion.
- Magnesium is a group 2A element, so it has a charge of +2 (Mg2+).
- Hypochlorite (ClO) has a charge of -1 based on the combination of its constituent elements.
- Since the overall charge should be neutral, the formula for magnesium hypochlorite is Mg(ClO)2.