2. Lewis structures of H2O

⇐ To index

 

1. Count the total number of electrons (NT) of the valence shell for all atoms of the molecule.

Wrong. Check the valence electrons of O and H.
Wrong. Check the valence electrons of O and H.
Right. O: 6; H: 1. Total 8 electrons

2. Select the central atom:

Right. In general it is the least electronegative atom,      hydrogen is excluded as a central atom.

Central atom O
Wrong. El átomo central es el menos electronegativo. El hidrógeno nunca actúa como átomo central.

3. How many electrons are used in single bonds:

Wrong. There are two bonds. Each one requires two electrons.
Right. The two O-H bonds require

4 electrones

4. How many electrons are needed to complete the valence shell of terminals atoms.

Right. Hydrogen can only accommodate two electrons      in the valence shell. Already shares two electrons in each O-H bond.

No more electrons
Wrong. Hydrogen atoms can only accommodate two electrons      in the valence shell. Already share two electrons in each O-H bond.

 

5. How many electrons are needed to complete the octet of the central atom?

Wrong. The O atom only shares 4 electrons with      H atoms. Requires more electrons to complete the octet.
Wrong. The O atom only shares 4 electrons with      H atoms. Requires more electrons to complete the octet.
Right The O atom shares 4 electrons with      H atoms. Requires 4 additional electrons to complete the octet. Place them

6. What should be the geometry of this molecule? Structures

Wrong. This molecule is of type AE2X2 and cannot have a linear structure.
Wrong. This molecule is of type AE2X2 not consistent with an angular structure.
Right This molecule is of type AE2X2 with a tetrahedral arrangement of bonds. The two bonding      electron pairs will be placed at angles of aproximately 109º

7. Is the molecule polar? Electronegativity y Polarity

Wrong. This molecule has polar bonds      with a non linear arrangement.
Right This molecule has polar bonds with an angular arrangement. The resulting dipolo moment will be non zero. Dipoles

8. What type of orbitals uses the central atom? Orbitals

Wrong. An sp hybridization implies      the existence of only two positions around the central atom.
No es correcto. Una hibridación sp2 supone la existencia de sólo tres posiciones alrededor del átomo central.
Correcto Los cuatro orbitales sp3 alojan los dos pares electrónicos libres y los dos de enlace (compartidos). Orbitales sp3