what is the lewis structure for MgCO3 ?
The Correct Answer and Explanation is:
Lewis Structure for MgCO₃ (Magnesium Carbonate):
Magnesium carbonate is an ionic compound composed of a magnesium ion (Mg²⁺) and a carbonate ion (CO₃²⁻). To draw the Lewis structure for MgCO₃, we must first understand the nature of the ions involved:
1. Magnesium ion (Mg²⁺):
Magnesium is an alkaline earth metal. It loses two electrons to form a Mg²⁺ cation. In Lewis structure notation, this is often simply written as “Mg²⁺” without any electron dots, since it has lost its valence electrons.
2. Carbonate ion (CO₃²⁻):
The carbonate ion is a polyatomic anion with a charge of -2. Carbon is the central atom, bonded to three oxygen atoms. One of the carbon–oxygen bonds is a double bond, and the other two are single bonds with extra lone pairs on the oxygen atoms to reflect the extra electrons from the charge. This creates resonance structures.
Lewis Structure of CO₃²⁻:
mathematicaCopyEdit O
||
C — O⁻
|
O⁻
or in resonance form:
mathematicaCopyEdit O⁻ O O
\ || /
C <——> C <——> C
/ \ \
O O⁻ O⁻
Each resonance form shows one C=O double bond and two C–O⁻ single bonds. The overall structure is a hybrid of these three forms, making all C–O bond lengths equal in reality.
Lewis Structure for MgCO₃:
MgCO₃ is not a covalent molecule. Instead, Mg²⁺ ion is ionically bonded to the CO₃²⁻ ion.
The Lewis structure of MgCO₃ is therefore represented as:
mathematicaCopyEditMg²⁺ [O=C–O⁻
|
O⁻]²⁻
Mg²⁺ is not covalently bonded, so its electrons are not shown. The negative charge is localized on the carbonate ion. The real structure of CO₃²⁻ includes resonance, so all three oxygen atoms are equivalent in terms of bonding.
Summary:
The Lewis structure of MgCO₃ consists of:
- A Mg²⁺ cation (with no valence electrons shown).
- A CO₃²⁻ anion showing resonance between three forms.
This reflects the ionic nature of the compound and the delocalized bonding in the carbonate ion.
