Question

covalent compounds: mastery test
5
select the correct answer.
what happens when an atom of sulfur combines with two atoms of chlorine to produce scl₂?
a. each chlorine atom shares a pair of electrons with the sulfur atom.
b. an electron is transferred from each chlorine atom to the sulfur atom.
c. an electron is transferred from the sulfur atom to each chlorine atom.
d. each chlorine atom shares all its valence electrons with the sulfur atom.
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Explanation:

• Option A: In \(SCl_2\), which is a covalent compound, chlorine (\(Cl\)) and sulfur (\(S\)) share electrons. Each chlorine atom shares a pair of electrons with the sulfur atom. Chlorine has 7 valence electrons (\(3s^{2}3p^{5}\)) and needs 1 more electron to complete its octet. Sulfur has 6 valence electrons (\(3s^{2}3p^{4}\)) and needs 2 more electrons to complete its octet. So, each \(Cl\) atom shares a pair of electrons (one from \(Cl\) and one from \(S\)) with \(S\) atom.
• Option B: If an electron is transferred from each chlorine atom to the sulfur atom, it would form an ionic compound. But \(SCl_2\) is a covalent compound (formed between two non - metals \(S\) and \(Cl\)), so electron transfer (which is characteristic of ionic bond formation) does not occur.
• Option C: If an electron is transferred from the sulfur atom to each chlorine atom, it would also imply an ionic bond formation. Since \(S\) and \(Cl\) are non - metals and \(SCl_2\) is covalent, this is incorrect.
• Option D: Chlorine has 7 valence electrons. If each chlorine atom were to share all its valence electrons, it would exceed the octet rule (more than 8 electrons around \(Cl\) in an uncharged state is not typical for main - group elements in simple covalent compounds). Chlorine only shares 1 pair of electrons (1 electron from \(Cl\) and 1 from \(S\)) to complete its octet.

Answer:

A. Each chlorine atom shares a pair of electrons with the sulfur atom.