What is the oxidation number of PO4 in the compound Ca3(PO4)2? how do you get it?
You know the PO4 has a net charge of -3
by the rules, O is -2, so 4 of those makes O carry a total of -3
Finally, the rules state then the sum of the oxidation numbers equals the charge...
X-8=-3
solve for X
6 years later
To determine the oxidation number of PO4 in the compound Ca3(PO4)2, follow these steps:
1. Identify the known oxidation numbers of the other elements in the compound:
- Calcium (Ca) is in Group 2 of the periodic table, so it has an oxidation number of +2.
- Oxygen (O) usually has an oxidation number of -2, unless it is bonded to a more electronegative element or in a peroxide, superoxide, or when oxygen is in its elemental form.
2. Use the known oxidation numbers to calculate the oxidation number of PO4.
- Since two calcium ions (Ca2+) are present and each has a charge of +2, the total positive charge is +2 x 3 = +6.
- The total negative charge must equal the total positive charge.
- There are four oxygen atoms (O) in PO4, each with a charge of -2. Therefore, the total negative charge from oxygen is -2 x 4 = -8.
- To achieve overall charge neutrality, the sum of the oxidation numbers in the phosphate group (PO4) must be equal to the total charge on the compound.
- Let the oxidation number of PO4 be x. We have x + (-8) + 6 = 0.
- Simplifying this equation, we get x - 2 = 0.
- Solving for x, x = +2.
Therefore, the oxidation number of PO4 in the compound Ca3(PO4)2 is +2.
To determine the oxidation number of PO4 in the compound Ca3(PO4)2, you need to consider a few factors.
First, we need to understand the oxidation numbers of the individual elements. In general, the oxidation number of calcium (Ca) is +2 since it is an alkali earth metal and tends to lose two electrons.
Next, we need to consider the overall charge of the compound. The compound is neutral, so the overall charge is 0.
Now, let's break down the compound: Ca3(PO4)2. The subscript 3 indicates that there are three calcium ions (Ca2+), and the subscript 2 indicates that there are two phosphate ions (PO4) in the compound.
Since the compound is neutral, the sum of all the oxidation numbers should add up to zero.
Let's assume the oxidation number of PO4 is x. Since there are two phosphate ions, the total charge contributed by the phosphate ions will be 2x.
Calcium, being in Group 2 of the periodic table, has an oxidation number of +2. So, the total charge contributed by the calcium ions will be 3(+2) = +6.
Since the overall charge of the compound is 0, we can write the equation:
2x + 6 = 0
By solving this equation, we find that x = -3.
Therefore, the oxidation number of PO4 in the compound Ca3(PO4)2 is -3.
In summary, to get the oxidation number of PO4 in Ca3(PO4)2, we considered the oxidation numbers of the other elements in the compound (in this case, calcium) and the overall charge of the compound. We then set up an equation and solved for the oxidation number.