Write chemical formulas for the compounds formed between the following positive and negative ions.

Question

(a) Na+ and OH-

(b) Fe3+ and ClO4-

(c) Ba2+ and CO32-

(d) Al3+ and NO3-

Answer 1

The charges on each ion become the number of the opposite ion.

Also, if there is no number, just a positive or negative sign, this means the charge is 1.

For example, if we combined Mg2+ and Br- the resulting substance would be MgBr₂

(a) Na+ and OH-

Na¹⁺ + OH^1- ---> NaOH

.......................................

(b) Fe3+ and ClO4-

Fe³⁺ + ClO₄^1- ---> Fe(ClO₄)₃

.......................................

(c) Ba2+ and CO32-

Ba²⁺ + CO₃^2- ---> Ba₂(CO₃)₂ ---> Ba(CO₃)

The two's cancel out!

.......................................

(d) Al3+ and NO3-

Al³⁺ + NO₃^1- ---> Al(NO₃)₃