How many valence electrons are in the electron dot structure of H2O?
The Correct Answer and Explanation is:
The molecule H2O (water) consists of two hydrogen atoms and one oxygen atom. To determine the number of valence electrons in the electron dot structure of H2O, we can follow these steps:
1. Identify the number of valence electrons for each atom:
- Hydrogen (H): Hydrogen is in Group 1 of the periodic table, which means it has 1 valence electron.
- Oxygen (O): Oxygen is in Group 16, meaning it has 6 valence electrons.
2. Count the total number of valence electrons:
- The molecule H2O has 2 hydrogen atoms and 1 oxygen atom.
- Therefore, the total number of valence electrons is calculated as: Total valence electrons=(2×1 (from H))+(1×6 (from O))=2+6=8 valence electrons.\text{Total valence electrons} = (2 \times 1 \, \text{(from H)}) + (1 \times 6 \, \text{(from O)}) = 2 + 6 = 8 \, \text{valence electrons}.Total valence electrons=(2×1(from H))+(1×6(from O))=2+6=8valence electrons.
3. Draw the electron dot structure:
To draw the electron dot structure, follow these steps:
- The oxygen atom is in the center since it is more electronegative than hydrogen.
- Each hydrogen atom shares its one electron with oxygen, forming a covalent bond.
- Oxygen has 6 valence electrons, so after forming bonds with the two hydrogen atoms, 4 electrons (2 lone pairs) remain on the oxygen atom.
4. Verify the octet rule:
- Oxygen: In the structure, oxygen will have 2 shared electrons from each hydrogen atom (making 4 electrons from bonds) and 4 remaining electrons as lone pairs. Oxygen satisfies the octet rule by having 8 electrons around it.
- Hydrogen: Each hydrogen atom will have 2 electrons (one from the bond with oxygen), which satisfies the duet rule for hydrogen.
Thus, the molecule H2O has 8 valence electrons in total, and the electron dot structure reflects this distribution.
