Draw a Lewis dot structure for AgCl and Co(NO3)2.
The Correct Answer and Explanation is:
Here are the Lewis dot structures and explanations for AgCl and Co(NO₃)₂.
Lewis Dot Structure for AgCl
AgCl (Silver chloride):
Ag is a metal and forms a +1 ion (Ag⁺), while Cl is a halogen that forms a -1 ion (Cl⁻). The bonding in AgCl is ionic, not covalent, so the Lewis structure is represented by showing ions with their charges and valence electrons.
Structure:
Ag⁺ :Cl:⁻
(6 lone pair electrons around Cl)
Chloride ion (Cl⁻) has 8 valence electrons in total. It gains one electron from Ag to complete its octet. Silver loses one electron, becoming Ag⁺.
Lewis Dot Structure for Co(NO₃)₂
Co(NO₃)₂ (Cobalt(II) nitrate):
Cobalt(II) nitrate consists of a Co²⁺ ion and two NO₃⁻ (nitrate) ions. Each nitrate ion contains one nitrogen atom bonded to three oxygen atoms. One of the bonds is a double bond while the other two are single bonds with negative charges delocalized across the oxygen atoms. The structure is stabilized through resonance.
Structure (simplified representation):
[O=N⁺–O⁻]
|
O⁻
Each nitrate ion looks like this, with resonance between the three oxygen atoms. The nitrogen is at the center forming one double bond and two single bonds with oxygens. Due to resonance, each N–O bond has a bond order of approximately 1.33.
Cobalt exists as Co²⁺ and is ionically bonded to two NO₃⁻ ions. The overall compound is neutral.
Explanation
AgCl is a simple ionic compound formed from a transition metal, silver (Ag), and a halogen, chlorine (Cl). Silver readily loses one electron to form a stable Ag⁺ ion. Chlorine, with seven valence electrons, gains this electron to complete its octet and becomes Cl⁻. Since AgCl is ionic, the Lewis dot structure is best represented by showing Ag⁺ without electrons and Cl⁻ surrounded by eight electrons, indicating a full valence shell. The strong electrostatic attraction between these ions holds them together in a crystal lattice in solid form.
Co(NO₃)₂ is a more complex ionic compound. Cobalt in this compound has a +2 oxidation state, so it forms the Co²⁺ cation. The nitrate ion (NO₃⁻) is a polyatomic ion consisting of one nitrogen atom covalently bonded to three oxygen atoms. One of these bonds is a double bond while the other two are single bonds with extra electrons, making the oxygens negatively charged. However, the negative charge is delocalized through resonance, making all N–O bonds equivalent in length and strength. Each nitrate carries a -1 charge, and with two nitrate ions, the total negative charge is -2, balancing the +2 charge of cobalt.
The bond between cobalt and nitrate is ionic, as cobalt loses electrons to form a cation and each nitrate ion gains one electron. The nitrate ions themselves contain covalent bonds internally, but the overall attraction between Co²⁺ and NO₃⁻ is ionic. Lewis structures help illustrate the ionic and covalent character in such mixed compounds and are essential for understanding electron arrangement and reactivity
.
