predict how many sodium ions would combine with:
(a) a chlorine ion.
(b) a carbonate ion.
(c) a phosphate ion.
You need to know the valences of the Na^+ (which is +1) and the valences of the anions. Chloride ion is -1. The others are listed at this site.
http://www.woodrow.org/teachers/chemistry/links/chem1/PolyatomicIonsChart.html
To predict the number of sodium ions that would combine with different ions, we need to look at the charges of each ion and find the ratio that balances the charges.
(a) Sodium combines with a chlorine ion (Cl-).
Sodium (Na+) carries a positive charge, while chlorine (Cl-) carries a negative charge. Since the charges on the ions are opposite and equal in magnitude, one Na+ ion will combine with one Cl- ion to balance the charges. Therefore, the number of sodium ions that would combine with a chlorine ion is 1.
(b) Sodium combines with a carbonate ion (CO3^2-).
Sodium (Na+) carries a positive charge, while carbonate (CO3^2-) carries a negative charge. To balance the charges, the sodium ion needs to combine with two carbonate ions. This is because the charge of the carbonate ion is -2, so two Na+ ions are required to neutralize the charge. Therefore, the number of sodium ions that would combine with a carbonate ion is 2.
(c) Sodium combines with a phosphate ion (PO4^3-).
Sodium (Na+) carries a positive charge, while phosphate (PO4^3-) carries a negative charge. To balance the charges, three sodium ions are required to neutralize the charge of the phosphate ion. This is because the charge of the phosphate ion is -3, so three Na+ ions are needed. Therefore, the number of sodium ions that would combine with a phosphate ion is 3.
In summary:
(a) One sodium ion would combine with one chlorine ion.
(b) Two sodium ions would combine with one carbonate ion.
(c) Three sodium ions would combine with one phosphate ion.