Potassium and sulfur react to form an ionic compound. What is the correct formula of the compound formed?
A. [tex]K _2 S[/tex]
B. PS
C. [tex]P _2 S_3[/tex]
D. [tex]2 K^{+} S ^{2-}[/tex]
Answer (1)
Potassium forms a +1 ion ( K + ) and sulfur forms a -2 ion ( S 2 − ).
Balance the charges to achieve a neutral compound: two potassium ions are needed for each sulfur ion.
Write the chemical formula with the cation first and the anion second.
The correct formula is K 2 S .
Explanation
Understanding the Problem Potassium (K) and sulfur (S) react to form an ionic compound. We need to determine the correct formula of the resulting ionic compound.
Identifying the Ions Potassium is in group 1 of the periodic table, so it tends to lose one electron to form a +1 ion ( K + ). Sulfur is in group 16, so it tends to gain two electrons to form a -2 ion ( S 2 − ).
Balancing the Charges To form a neutral compound, the total positive charge must equal the total negative charge. We need two potassium ions ( K + ) to balance the charge of one sulfur ion ( S 2 − ). This gives us 2 × ( + 1 ) + 1 × ( − 2 ) = 0 .
Writing the Formula The chemical formula is written with the cation (potassium) first and the anion (sulfur) second. The subscripts indicate the number of each ion needed to balance the charges. Therefore, the correct formula is K 2 S .
Final Answer The correct formula for the ionic compound formed between potassium and sulfur is K 2 S .
Examples
Ionic compounds like potassium sulfide ( K 2 S ) are crucial in various applications. For instance, they can be used in the production of fertilizers to provide essential nutrients for plant growth. Understanding how these compounds form helps us create more effective fertilizers, leading to better crop yields and sustainable agriculture. Additionally, K 2 S can be found in some specialized chemical processes, such as in certain types of batteries or in the synthesis of other sulfur-containing compounds. Knowing the correct formula ensures accurate usage and prevents unintended reactions.
