Question

1. what is the formula for lithium sulfide?

a) lis

b) \\(\text{li}_2\text{s}\\)

c) \\(\text{lis}_2\\)

d) \\(\text{li}_2\text{s}_2\\)

Explanation:

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<reasoning>

Identify ionic charges of constituent elements

\[

$$\begin{aligned} &\text{Lithium (Li): Group 1 metal} ightarrow \text{Li}^+\\ &\text{Sulfur (S): Group 16 nonmetal} ightarrow \text{S}^{2-} \end{aligned}$$

\]

Balance charges to find chemical formula

\[

$$\begin{aligned} &2(\text{Li}^+) + 1(\text{S}^{2-}) = 0\\ &\text{Formula} = \text{Li}_2\text{S} \end{aligned}$$

\]
</reasoning>

<answer>
<mcq-option>A) LiS</mcq-option>
<mcq-correct>B) \(\text{Li}_2\text{S}\)</mcq-correct>
<mcq-option>C) \(\text{LiS}_2\)</mcq-option>
<mcq-option>D) \(\text{Li}_2\text{S}_2\)</mcq-option>
</answer>

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Answer:

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<reasoning>

Identify ionic charges of constituent elements

\[

$$\begin{aligned} &\text{Lithium (Li): Group 1 metal} ightarrow \text{Li}^+\\ &\text{Sulfur (S): Group 16 nonmetal} ightarrow \text{S}^{2-} \end{aligned}$$

\]

Balance charges to find chemical formula

\[

$$\begin{aligned} &2(\text{Li}^+) + 1(\text{S}^{2-}) = 0\\ &\text{Formula} = \text{Li}_2\text{S} \end{aligned}$$

\]
</reasoning>

<answer>
<mcq-option>A) LiS</mcq-option>
<mcq-correct>B) \(\text{Li}_2\text{S}\)</mcq-correct>
<mcq-option>C) \(\text{LiS}_2\)</mcq-option>
<mcq-option>D) \(\text{Li}_2\text{S}_2\)</mcq-option>
</answer>

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