Question

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how do I prove a chemical formula of a compound using the Lewis structure ??

Answer 1

To prove the chemical formula of a compound using the Lewis structure, you need to follow these steps:

1. Draw the Lewis structure of the compound: Start by drawing the Lewis structure of the compound using the valence electrons of each atom. The valence electrons are the outermost electrons of an atom, which participate in chemical bonding. To determine the valence electrons of an atom, you can refer to its position in the periodic table.

2. Determine the number of electrons in the compound: Count the total number of valence electrons in the compound by adding up the valence electrons of each atom in the compound. This number is equal to the sum of the valence electrons of all the atoms in the compound.

3. Determine the number of electron pairs in the compound: Count the number of electron pairs in the compound by dividing the total number of valence electrons by 2. This gives you the number of electron pairs in the compound.

4. Determine the connectivity of the atoms: Identify the connectivity of the atoms in the compound by drawing the lines that connect the atoms in the Lewis structure. Each line represents a bond between the atoms.

5. Determine the formal charge of each atom: Calculate the formal charge of each atom in the compound by subtracting the number of lone pair electrons and half the number of bonding electrons from the total number of valence electrons for that atom. The formal charge of an atom should be as close to zero as possible.

6. Write the chemical formula: Write the chemical formula of the compound by using the symbol of each atom in the compound, along with its subscript, which corresponds to the number of atoms of each element present in the compound.

By following these steps, you can use the Lewis structure of a compound to prove its chemical formula.

Answer 2

1. Determine the total number of valence electrons in the molecule or ion.

• Add together the valence electrons from each atom. (Recall that the number of valence electrons is indicated by the position of the element in the periodic table.)

•If the species is a polyatomic ion, remember to add or subtract the number of electrons necessary to give the total charge on the ion.

2. Arrange the atoms to show specific connections.

• When there is a central atom, it is usually the least electronegative element in the compound.

• Chemists usually list this central atom first in the chemical formula, which is another clue to the compound’s structure.

• Hydrogen and the halogens are almost always connected to only one other atom, so they are usually terminal rather than central.

3. Place a bonding pair of electrons between each pair of adjacent atoms to give a single bond.

• In H2O, for example, there is a bonding pair of electrons between oxygen and each hydrogen.

4. Beginning with the terminal atoms, add enough electrons to each atom to give each atom an octet (two for hydrogen).

• These electrons will usually be lone pairs.

5. If any electrons are left over, place them on the central atom.

• Some atoms are able to accommodate more than eight electrons.

6. If the central atom has fewer electrons than an octet, use lone pairs from terminal atoms to form multiple (double or triple) bonds to the central atom to achieve an octet.

• This will not change the number of electrons on the terminal atoms.

7. Final check

• Always make sure all valence electrons are accounted for and each atom has an octet of electrons except for hydrogen (with two electrons).