Draw a suitable Lewis structure for Li2S. In the structure,
there are two sulfide ions and one lithium ion.
there are two lithium atoms and one sulfur atom with 6 electrons.
each lithium atom makes one bond to sulfur.
there are two lithium ions each with a +1 charge and one sulfide ion with four pairs of electrons and a -2 charge.
The correct answer and explanation is :
Lewis Structure for Lithium Sulfide (Li₂S)
To draw the Lewis structure of lithium sulfide (Li₂S), we need to follow these steps:
- Determine the number of valence electrons:
- Lithium (Li) is an alkali metal in Group 1, so each lithium atom has 1 valence electron.
- Sulfur (S) is a Group 16 element, so sulfur has 6 valence electrons.
- Total number of valence electrons:
- There are 2 lithium atoms, each contributing 1 electron, and 1 sulfur atom contributing 6 electrons.
- Total valence electrons = 2 (from Li) + 6 (from S) = 8 valence electrons.
- Structure Formation:
- Lithium forms Li⁺ ions by losing its single valence electron. Each lithium atom gives up 1 electron, leaving a +1 charge on each lithium atom.
- Sulfur, which has 6 valence electrons, needs 2 more electrons to complete its octet. Sulfur accepts the 2 electrons from the lithium atoms to form a S²⁻ ion.
- Bonding:
- Each lithium atom donates 1 electron to sulfur, forming an ionic bond between each lithium and sulfur.
- The sulfide ion (S²⁻) now has a full octet (8 electrons) and carries a -2 charge.
- The lithium ions (Li⁺) each have a +1 charge.
- Final Structure:
- The resulting ionic compound consists of two lithium cations (Li⁺) and one sulfide anion (S²⁻).
- In the Lewis structure, lithium ions are shown with their positive charges, and the sulfide ion has 8 electrons around it (4 pairs), with a -2 charge.
Explanation:
In lithium sulfide (Li₂S), the bonding is ionic. Lithium atoms lose electrons to form Li⁺ ions and sulfur gains electrons to form a S²⁻ ion. Since lithium only has one electron to donate, it forms a bond with sulfur by transferring its electron. The result is an ionic compound where the two lithium ions (Li⁺) are attracted to the sulfide ion (S²⁻) due to electrostatic forces.
Lewis Structure:
Li⁺ Li⁺
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S²⁻The structure shows each lithium ion (Li⁺) with a positive charge, the sulfide ion (S²⁻) with eight electrons (four pairs), and a negative charge of -2.