Describe the Lewis structure for the ionic compound calcium chloride, CaCl2.
The structure would include a Cl with 7 dots a 1- charge but with no square brackets. The structure would include a Cl with 8 dots in square brackets with a 2+ charge. The structure would include a Ca with no dots a 2+ charge but with no square brackets. The structure would include a Ca with no dots in square brackets with a 2+ charge.
The Correct Answer and Explanation is:
Lewis Structure for Calcium Chloride (CaCl₂)
The correct Lewis structure for CaCl₂, an ionic compound, shows the transfer of electrons from the metal (calcium) to the non-metal (chlorine):
- Ca: Calcium atom has 2 valence electrons. It loses both electrons to become Ca²⁺, a cation with no dots (no valence electrons left). Since it is an ion, we show it as:
[Ca]²⁺ (in square brackets with 2+ charge and no dots) - Cl: Each chlorine atom has 7 valence electrons. It gains 1 electron to complete its octet, becoming Cl⁻ with 8 electrons (dots) around it. Since it’s an ion, it should be written in square brackets with the charge:
[Cl⁻] (in square brackets with 8 dots and 1– charge)
So, the correct Lewis structure for CaCl₂ would be:
[Ca]²⁺ [Cl]⁻ [Cl]⁻
:Cl: :Cl:
.. .. .. ..
Each Cl⁻ has a full octet (8 dots) around it in square brackets with a –1 charge, and Ca²⁺ is in square brackets with no dots and a +2 charge.
Explanation (Approx. 300 Words)
Calcium chloride (CaCl₂) is an ionic compound formed between a metal (calcium) and a non-metal (chlorine). In ionic bonding, electrons are transferred from the metal to the non-metal.
Calcium (Ca), a Group 2 element, has two valence electrons. To become stable, it loses both electrons, forming a Ca²⁺ ion. This ion has no valence electrons (hence no dots in the Lewis structure) and is shown with a 2+ charge. Because it is an ion, it should be placed in square brackets: [Ca]²⁺.
Chlorine (Cl), a Group 17 element, has 7 valence electrons and needs one more to complete its octet. Each Cl atom gains one electron, forming a Cl⁻ ion with 8 valence electrons (represented as 8 dots). Each Cl⁻ is placed in square brackets with a 1– charge: [Cl]⁻.
Since one Ca²⁺ gives up 2 electrons, and each Cl⁻ only accepts 1 electron, two chlorine atoms are needed to balance the charge. The resulting compound is electrically neutral, with a ratio of 1:2 (CaCl₂).
In summary, the Lewis structure of CaCl₂ consists of one [Ca]²⁺ ion (no dots) and two [Cl]⁻ ions (8 dots each). The use of square brackets and charges correctly shows the ionic nature and electron transfer in the compound.
