Draw the Lewis structure for the hypochlorite ion, $ClO^{-}$. Include lone pairs and formal charges.
Answer (2)
Calculate the total valence electrons: 7 ( Cl ) + 6 ( O ) + 1 ( c ha r g e ) = 14 .
Form a single bond between Cl and O, using 2 electrons.
Distribute the remaining 12 electrons as lone pairs: 3 lone pairs on Cl and 3 lone pairs on O.
Calculate formal charges: Cl has 0, O has -1.
Explanation
Understanding the Problem We want to draw the Lewis structure for the hypochlorite ion, Cl O − . This involves determining the arrangement of atoms, the number of valence electrons, and the placement of lone pairs and formal charges.
Calculating Valence Electrons First, we need to calculate the total number of valence electrons. Chlorine (Cl) has 7 valence electrons, oxygen (O) has 6 valence electrons, and the ion has a -1 charge, which means there is an additional electron. So, the total number of valence electrons is 7 + 6 + 1 = 14 .
Forming the Single Bond Next, we draw a single bond between Cl and O: Cl-O. This single bond accounts for 2 electrons. We have 14 − 2 = 12 electrons remaining to distribute as lone pairs.
Adding Lone Pairs We distribute the remaining 12 electrons as lone pairs around the Cl and O atoms to satisfy the octet rule. We place three lone pairs (6 electrons) on the Cl atom and three lone pairs (6 electrons) on the O atom. This gives each atom 8 electrons (an octet).
Calculating Formal Charges Now, we calculate the formal charges on Cl and O. The formula for formal charge is: Formal charge = (Valence electrons) - (Non-bonding electrons) - (1/2 Bonding electrons).
For Cl: Formal charge = 7 − 6 − ( 1/2 × 2 ) = 7 − 6 − 1 = 0 .
For O: Formal charge = 6 − 6 − ( 1/2 × 2 ) = 6 − 6 − 1 = − 1 .
Drawing the Lewis Structure Finally, we draw the Lewis structure with the calculated lone pairs and formal charges. The oxygen atom has a formal charge of -1, and the chlorine atom has a formal charge of 0. The Lewis structure is: O with three lone pairs, single bonded to Cl with three lone pairs, and the entire structure in brackets with a -1 charge outside the brackets.
Examples
Lewis structures are used in chemistry to visualize the bonding between atoms in a molecule or ion. For example, understanding the Lewis structure of ozone ( O 3 ) helps explain its role in absorbing UV radiation in the stratosphere, protecting life on Earth. Similarly, Lewis structures are crucial in designing new drugs and materials by predicting how molecules will interact.
The Lewis structure for the hypochlorite ion, Cl O − , shows a chlorine atom single bonded to an oxygen atom with three lone pairs on both atoms. The oxygen carries a formal charge of -1, while chlorine has a formal charge of 0, indicating their respective electron distributions. This structure is useful for predicting the ion's reactivity in chemical processes.
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