Draw a suitable Lewis structure for Li2S. In the structure,
A. there are two lithium ions each with a +1 charge and and one sulfide ion with four pairs of electrons and a -2 charge.
B. there are two sulfide ions and one lithium ion.
C. there are wto lithium atoms and one sulfur atom with 6 electrons.
D. each lithium atom makes one bond to sulfur.
The Correct Answer and Explanation is :
The correct answer is A.
Explanation:
Lithium sulfide (Li₂S) consists of two lithium (Li) atoms and one sulfur (S) atom. To determine the Lewis structure of Li₂S, we need to consider the electronic configuration and bonding behavior of lithium and sulfur.
- Lithium’s Electron Configuration:
- Lithium is an alkali metal with the electron configuration ( 1s^2 2s^1 ).
- Lithium atoms tend to lose one electron to achieve a stable electron configuration, which results in a lithium ion (( Li^+ )) with a +1 charge.
- Sulfur’s Electron Configuration:
- Sulfur is a non-metal in Group 16 with an electron configuration of ( [Ne] 3s^2 3p^4 ).
- Sulfur needs to gain two electrons to complete its octet and achieve a stable electron configuration. Thus, sulfur tends to form a sulfide ion (( S^{2-} )) with a -2 charge.
- Ionic Bonding in Li₂S:
- Lithium atoms each lose one electron, forming two ( Li^+ ) ions.
- The sulfur atom gains two electrons to form one ( S^{2-} ) ion.
- The electrostatic attraction between the ( Li^+ ) ions and the ( S^{2-} ) ion holds the compound together.
Lewis Structure of Li₂S:
- The two lithium ions (( Li^+ )) are each surrounded by a +1 charge.
- The sulfide ion (( S^{2-} )) has four pairs of electrons around it, making it negatively charged with a -2 charge.
- Since lithium donates one electron and sulfur accepts two electrons, we end up with a formula of ( Li_2S ), where the ionic charges are balanced.
Thus, option A correctly describes the structure of Li₂S with two lithium ions, each with a +1 charge, and one sulfide ion with four pairs of electrons and a -2 charge.