Chapter 12 Question

Question

Potassium reacts with a certain element to form a compound with general formula K₂X. What would the most likely formula be formed between aluminum and the element X? Explain.

Answer 1

The formula K₂X indicates that it comprised 2 K⁺ ions and one X^2– ion.

We know that the potassium (K) ion has a +1 charge because of its position in the periodic table.

In ionic compounds, aluminum (Al) forms Al³⁺ ions (determined by its position in the periodic table).

The ionic compound formed between Al and the element X

would be comprised of 2 Al³⁺ ions and 3 X^2– ions

so that the positive charge of the Al³⁺ ions is balanced by the negative charge of the X^2– ions.

So ionic compound formed between Al and the element X would have the formula

Al₂X₃