Write the compound formulas for each of the following pairs and the name of the compound formed when the elements or radicals combine.
Mg+2 + OH-1
K+1 + PO4-3
Cu+2 + S-2
N+5 + O-2
Compounds have zero charge. Therefore, for magnesium hydroxide, the first one, it will be Mg(OH)2.
Mg is +2 and 2 OH at -1 each makes -2 and +2 + (-2) = 0. I shall be happy to check the others for you.
K+1 + PO4-3= K(PO4)Phosphoric acid
Cu+2 + S-2= CuS Copper(II)Sulfide
N+5 + O-2= NO3 Ammonia
N+5 + O-2= NO3 Nitrate
You need to redo these. All are incorrect. Both formulas and names are incorrect. For the first one, note the charge. You have one +1 charge for K and one -3 charge for PO4^-. That doesn't add to zero. You must have three of the +1 (to make +3) so it will add to one of the -3 to make zero.
K3PO4 is the formula. I KNOW that isn't hard so you must have something else about the procedure causing trouble. Explain in detail so I will know where to start. As for the names, name the + ion first and the negativae ion next. For polyatomic ions, here is a site that will help.
http://www.woodrow.org/teachers/chemistry/links/chem1/PolyatomicIonsChart.html
I stand corrected. CuS is the correct formula for copper(II) sulfide and you have the correct name for it also.
K+1 + PO4-3= K3PO4 potassium sulfate
N+5 + O-2= NO nitrogen(II)oxide
I added -3 to the O-2 to get a negative 5
1. K3PO4 is correct. The name, however, is not. Look again at the link I gave you for polyatomic ions and look up PO4^-3 ion.
2. You CHANGED the number on O and you can't do that. If O is listed as -2, then a -2 it is and it must stay a -2.
N is +5
O is -2
10 is the lowest common multiple. How many N must we have to make 10. How many O must we have to make 10. Will that make it zero. Another way to do this is to cross the numbers. That works this way. I'll show you on the K3PO4.
Write the valences just above the letter, something like this.
K+1PO44-3
Now, mentally, form a large X so that the top of the left part of the X is the +1. Bring that number down (not the sign) to the bottom of that line. So a 1 is the subscript for PO4. The -3 is at the top of the right hand side of the X. Bring it down to the left and it becomes the subscript for K. Again, ignore the sign and the number is 3. The final product looks like this
K3(PO4)1.
Of course, when the number is 1 it isn't needed and the final formula would be K3PO4. Try that method on the N and O and see if ti works better for you.
N+5 O-2
X
2 5 = N2O5
and the name for K3PO4 is potassium phosphate?
N2O5 is right.
potassium phosphate is right.
The name for N2O5. The
"old" name was nitrogen pentoxide, and some still name it that way, but the new name is dinitrogen pentoxide.