Write the empirical formula of at least four binary ionic compounds that could be formed from the following ions:
[tex]$Mg^{2+}, Ni^{4+}, Cl^{-}, S^{2-}$[/tex]
Answer (1)
Determine the charges of the given ions: M g 2 + , N i 4 + , C l − , S 2 − .
Combine each cation with each anion to achieve charge neutrality.
Find the smallest whole number ratio of ions to balance the charges.
Write the empirical formulas: M g C l 2 , M g S , N i C l 4 , N i S 2 . M g C l 2 , M g S , N i C l 4 , N i S 2
Explanation
Understanding the Problem We are asked to write the empirical formulas of at least four binary ionic compounds formed from the ions M g 2 + , N i 4 + , C l − , and S 2 − . A binary ionic compound consists of two elements, one a metal (cation) and the other a nonmetal (anion). The compound must be electrically neutral, meaning the total positive charge must equal the total negative charge.
Solution Plan We will combine each cation with each anion to form a neutral compound. To do this, we need to find the smallest whole number ratio of ions that results in a neutral compound for each combination. Then, we will write the empirical formula for each compound.
Magnesium and Chlorine Combination
Magnesium and Chlorine: M g 2 + and C l − . To balance the +2 charge of magnesium, we need two chloride ions, each with a -1 charge. Thus, the formula is M g C l 2 .
Magnesium and Sulfur Combination
Magnesium and Sulfur: M g 2 + and S 2 − . The charges are equal and opposite (+2 and -2), so they balance in a 1:1 ratio. The formula is M g S .
Nickel and Chlorine Combination
Nickel and Chlorine: N i 4 + and C l − . To balance the +4 charge of nickel, we need four chloride ions, each with a -1 charge. Thus, the formula is N i C l 4 .
Nickel and Sulfur Combination
Nickel and Sulfur: N i 4 + and S 2 − . To balance the +4 charge of nickel, we need two sulfide ions, each with a -2 charge. Thus, the formula is N i S 2 .
Final Answer Therefore, the empirical formulas of four binary ionic compounds formed from the given ions are M g C l 2 , M g S , N i C l 4 , and N i S 2 .
Examples
Understanding how ions combine to form neutral compounds is crucial in various real-world applications. For instance, in agriculture, knowing the empirical formulas of compounds like magnesium sulfate ( M g S O 4 ) helps farmers determine the correct amount of fertilizer to use. Similarly, in medicine, understanding the composition of compounds like sodium chloride ( N a Cl ) is essential for preparing intravenous solutions. In materials science, the formation of compounds like titanium dioxide ( T i O 2 ) is vital for creating pigments and coatings. These examples highlight the practical importance of understanding ionic compound formation in diverse fields.
