Question

How to find formulas for different salts when looking at ions?


For example: Na+ and NO-3


Thanks a lot!

Answer 1

Answer:

formula is NaNO3

Explanation:

By doing crossing over between the ion we can find the formula

for example

Na+ (NO3)-1

after cross over

NaNO3

Answer 2

Answer:

Explanation:Salts are ionic compounds which, when dissolved in water, break up completely into ions. They arise by the reaction of acids with bases, and they always contain either a metal cation or a cation derived from ammonium (NH4+).

Examples of salts include NaCl, NH4F, MgCO3, and Fe2(HPO4)3.

Salts are named by listing the names of their component ions, cation first, then anion. This involves three distinct steps.

Split the Formula in Two

Start by making a vertical slice through the formula just after the metal or ammonium:

NaCl Na|Cl

NH4F NH4|F

MgCO3 Mg|CO3

Fe2(HPO4)3 Fe2|(HPO4)3

Step 2: Determine the Charges On the Ions

Determine the ions and their charges on each half. This is definitely the tricky part. Seven rules here are helpful:

Rule 1: Group 1 metals (Li – Fr) are all 1+

Rule 2: Group 2 metals (Be – Ra) are all 2+

Rule 3: Aluminum is 3+; Ammonium is 1+

Rule 4: All other metals require a Roman numeral

Rule 5: Group 7 nonmetals (F – I) are all 1–

Rule 6: Group 6 nonmetals (O – Te) AS ANIONS are usually 2–

Rule 7: The overall charge must be 0

For example:

NaCl Na|Cl Na+|Cl–

NH4F NH4|F NH4+|F–

MgCO3 Mg|CO3 Mg2+|CO32–

Fe2(HPO4)3 Fe2|(HPO4)3 Fe3+|HPO42–

Step 3: Name the Ions

Then name those ions:

NaCl Na+|Cl– sodium chloride

NH4F NH4+|F– ammonium fluoride

MgCO3 Mg2+|CO32– magnesium carbonate

Fe2(HPO4)3 Fe3+|HPO42– iron(III) hydrogen phosphate

Those ions, by the way, are called the principal species in solution for the salt. Figuring out the principal species in solution just this way gets to be REALLY important when you study equilibrium. You'll need to know those charges too, so you might as well learn them now and get it over with.

Tips for Success

A few more tips may be helpful:

There's no way around memorizing element names. Just do it.

Rule 7 is far more valuable than most beginners realize.

Can't remember or figure out the charge on the cation? Figure it out for the anion and make it all add up to 0.

Can't figure out the charge on the anion? Any chance Rule 1, 2, or 3 applies? If so, figure out the anion charge from the cation charge using Rule 7.

Stuck because you have a transition metal, such as Fe or Mn, and can't remember the charge on the anion? Look around for other examples of the anion being used. For example, say you have to name FeSO4 and you can't remember the charge on SO4. If you find "Na2SO4" somewhere else on the exam, quiz, or in the book, you're home free. With this information you'll know that SO4 must be 2–, and therefore the charge on Fe must be 2+.

If you know your strong acids, then you know "H2SO4." H here is H+, and the overall charge is 0. So SO4 must be 2–. Similarly,

HNO3 gives NO3–,

HClO3 gives ClO3–, and

HClO4 gives ClO4–.

This works with weak acids, too, if you can remember them, such as H2CO3 and H3PO4.

Learn lots of acid names, because they help here.

X-ic acids give X-ate anions (sulfuric/sulfate, nitric/nitrate)

X-ous acids give X-ite anions (nitrous/nitrite