Solution
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Certainly, the Lewis dot structure is a diagram that represents the valence electrons of an atom as dots around the elements' symbols. For a molecule like H2O (water), the Lewis dot structure can be drawn by following these steps:
1. Count the Total Number of Valence Electrons: Oxygen (O) has 6 valence electrons, and each Hydrogen (H) has 1 valence electron. Since there are two hydrogen atoms, the total number of valence electrons for H2O is 6 + 1(2) = 8 electrons.
1. Count the Total Number of Valence Electrons: Oxygen (O) has 6 valence electrons, and each Hydrogen (H) has 1 valence electron. Since there are two hydrogen atoms, the total number of valence electrons for H2O is 6 + 1(2) = 8 electrons.
1. Count the Total Number of Valence Electrons: Oxygen (O) has 6 valence electrons, and each Hydrogen (H) has 1 valence electron. Since there are two hydrogen atoms, the total number of valence electrons for H2O is 6 + 1(2) = 8 electrons.
2. Determine the Central Atom: In the case of H2O, oxygen is less electronegative than hydrogen and can form more bonds, so oxygen will be the central atom.
3. Place the Central Atom: Draw the symbol for oxygen (O) and place it in the center. Then, draw the symbols for hydrogen (H) on either side of the oxygen.
4. Distribute the Valence Electrons: Start by placing a pair of electrons (a single bond) between the oxygen and each hydrogen atom to connect them. This accounts for 4 of the 8 valence electrons (2 electrons per bond).
5. Complete the Octet for the Central Atom: Oxygen needs 8 electrons to complete its octet. It already shares 4 electrons with the hydrogen atoms, so you need to add 4 more electrons (as two lone pairs) to the oxygen atom.
6. Check the Formal Charges: Ensure that the formal charges on all atoms are as close to zero as possible. In the case of H2O, there are no formal charges since all atoms have their required number of electrons: oxygen has its octet, and each hydrogen has 2 electrons (its duet).
7. Review the Structure: Make sure that the total number of valence electrons used in the structure equals the number you calculated in step 1. For H2O, you should have used all 8 valence electrons.
The final Lewis dot structure for H2O should look like this:
```
H
\
O
/ \
H :
```
The two dots on the right side of the oxygen atom represent the lone pair of electrons. The lines between the oxygen and hydrogen atoms represent the shared pairs of electrons (bonds). Each hydrogen atom is bonded to the oxygen atom, and the oxygen atom has two additional lone pairs of electrons. This structure satisfies the octet rule for oxygen and the duet rule for hydrogen.
2. Determine the Central Atom: In the case of H2O, oxygen is less electronegative than hydrogen and can form more bonds, so oxygen will be the central atom.
3. Place the Central Atom: Draw the symbol for oxygen (O) and place it in the center. Then, draw the symbols for hydrogen (H) on either side of the oxygen.
4. Distribute the Valence Electrons: Start by placing a pair of electrons (a single bond) between the oxygen and each hydrogen atom to connect them. This accounts for 4 of the 8 valence electrons (2 electrons per bond).
5. Complete the Octet for the Central Atom: Oxygen needs 8 electrons to complete its octet. It already shares 4 electrons with the hydrogen atoms, so you need to add 4 more electrons (as two lone pairs) to the oxygen atom.
6. Check the Formal Charges: Ensure that the formal charges on all atoms are as close to zero as possible. In the case of H2O, there are no formal charges since all atoms have their required number of electrons: oxygen has its octet, and each hydrogen has 2 electrons (its duet).
7. Review the Structure: Make sure that the total number of valence electrons used in the structure equals the number you calculated in step 1. For H2O, you should have used all 8 valence electrons.
The final Lewis dot structure for H2O should look like this:
```
H
\
O
/ \
H :
```
The two dots on the right side of the oxygen atom represent the lone pair of electrons. The lines between the oxygen and hydrogen atoms represent the shared pairs of electrons (bonds). Each hydrogen atom is bonded to the oxygen atom, and the oxygen atom has two additional lone pairs of electrons. This structure satisfies the octet rule for oxygen and the duet rule for hydrogen.
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