Let's determine the correct formula for cesium sulfide by considering the valence (or oxidation states) of cesium (Cs) and sulfur (S).
1. Determine the valence of cesium and sulfur:
- Cesium (Cs) belongs to Group 1 of the periodic table and has a valence of +1.
- Sulfur (S) belongs to Group 16 of the periodic table and typically exhibits a valence of -2.
2. Balance the charges:
- To form a neutral compound, the total positive charge must equal the total negative charge.
- Each cesium ion (Cs^+) has a +1 charge.
- Each sulfide ion (S^2-) has a -2 charge.
3. Combine the ions in a ratio that balances the charges:
- To balance the -2 charge of one sulfide ion, we need two cesium ions, each contributing a +1 charge.
- Thus, we need two cesium ions (each +1) to balance one sulfide ion (-2).
4. Write the formula:
- The correct formula, which indicates that two cesium ions combine with one sulfide ion, is written as [tex]\( Cs_2S \)[/tex].
Given the options:
A. CsS
B. [tex]\( Cs_2S \)[/tex]
C. [tex]\( CsS_2 \)[/tex]
D. [tex]\( Cs_2S_2 \)[/tex]
The correct formula for cesium sulfide is option B: [tex]\( Cs_2S \)[/tex].
