How would I go about creating a Lewis Dot structure for the Calcium Carbonate and Magnesium Hydroxide?
I know how to do it for any compound with two elements such as SF5, but I don't know how to approach it when there's a polyatomic ion involved and there are three elements.
To create Lewis Dot structures for compounds involving polyatomic ions, such as calcium carbonate (CaCO3) and magnesium hydroxide (Mg(OH)2), follow these steps:
1. Identify the central atom: In both compounds, calcium (Ca) and magnesium (Mg) are the central atoms since they are less electronegative than the other atoms.
2. Determine the valence electrons: Find the total number of valence electrons for each atom in the compound. Calcium and magnesium are in Group 2 of the periodic table, so they each have 2 valence electrons. Oxygen (O) in carbonate (CO3) has 6 valence electrons, while hydrogen (H) and oxygen in hydroxide (OH) have 1 and 6 valence electrons, respectively.
3. Draw the skeletal structure: Connect the central atom(s) with the other atoms using single bonds. In calcium carbonate, the skeletal structure would be Ca-O-C≡O, where the oxygen atoms are double-bonded to the carbon atom. In magnesium hydroxide, the skeletal structure would be Mg-O-H.
4. Distribute the remaining valence electrons: Subtract the number of valence electrons already used in the skeletal structure from the total number of valence electrons for each atom. Distribute the remaining electrons around the atoms, prioritizing octet formation for all atoms except hydrogen.
For calcium carbonate (CaCO3):
- Calcium has 2 valence electrons, but it's bonded to three oxygen atoms, so it has used all of its valence electrons.
- Carbon has 4 valence electrons and needs 4 more to complete its octet, so it forms two double bonds with the oxygen atoms.
- Each oxygen atom has 6 valence electrons and needs 2 more to complete an octet, so they each form single bonds with the carbon atom.
For magnesium hydroxide (Mg(OH)2):
- Magnesium has 2 valence electrons, but it's bonded to two oxygen atoms and two hydrogen atoms, so it has used all of its valence electrons.
- Each oxygen atom has 6 valence electrons and needs 2 more to complete an octet, so they each form single bonds with the magnesium atom.
- Each hydrogen atom has 1 valence electron and needs 1 more to complete an octet, so they each form single bonds with the oxygen atoms.
5. Check for octet rule fulfillment: Ensure that all atoms (except hydrogen) have either 8 electrons or a full valence shell.
6. Add formal charges: If necessary, assign formal charges to make sure all atoms have a charge of zero or as close to zero as possible. This step may not be required for these particular compounds.
That's it! You have successfully created the Lewis Dot structures for calcium carbonate and magnesium hydroxide.
To create Lewis Dot structures for compounds with polyatomic ions, such as Calcium Carbonate (CaCO3) and Magnesium Hydroxide (Mg(OH)2), you need to follow a few steps:
1. Determine the total number of valence electrons: Find the number of valence electrons for each atom in the compound. For polyatomic ions like carbonate (CO3 2-) and hydroxide (OH-), take into account the charge of the polyatomic ion.
2. Identify the central atom: In both compounds, Calcium (Ca) and Magnesium (Mg) are the central atoms since they are less electronegative than the other elements.
3. Connect the atoms: Draw lines to represent chemical bonds between the central atom and each surrounding atom. Carbonate (CO3 2-) is a triatomic ion, so it will surround the central atom, forming double bonds with two of the oxygen atoms and a single bond with the remaining oxygen atom. Hydroxide (OH-) is a monatomic ion, so it will only have a single bond with the central atom.
4. Assign electron pairs: Place pairs of electrons (dots) around each atom, except for hydrogen (H), which can only accommodate one electron pair. Start by placing one pair of electrons between each bonded pair of atoms and then distribute the remaining electron pairs around the outer atoms to satisfy the octet rule. Remember to account for the charge of the polyatomic ion by adjusting the number of electrons.
5. Check for octets and formal charges: Ensure that each atom (except hydrogen) has a full octet (eight electrons) unless it is capable of expanding its octet. Also, check for any formal charges to make sure they add up to the overall charge of the compound. Adjust electron pairs as needed.
Once you have completed these steps, you will have created the Lewis Dot structures for Calcium Carbonate (CaCO3) and Magnesium Hydroxide (Mg(OH)2).
For MgCO3 you write the Mg^2+ with a + sign then CO3^2-; i.e., write the lewis dot structure for two ions of Mg and carbonate. Same for Mg(OH)2. I would write the Mg ion and write two OH ions.
Mg is is just Mg:
Mg^2+ is Mg^2+.
Here is a site that will show you CO3^2-
http://en.wikipedia.org/wiki/Carbonate
You will need to add the other electrons but this shows the bonding.