Question

1. considering the water molecule which on the surface seems to be geometrically linear symmetrical but in reality is bent and shaped like a “v” is actually a polar bond, why is this true?
2. explain what the difference is between intermolecular bonds and intramolecular bonds. which one of the two is responsible for the chemical properties of a molecule?

Explanation:

• Question 17: The oxygen atom in \(H_2O\) has two lone pairs of electrons. These lone pairs repel the bonding pairs (the \(O - H\) bonds). As a result, the \(H - O - H\) bond angle is about \(104.5^{\circ}\) (bent shape). Oxygen is more electronegative than hydrogen. In the \(O - H\) bonds, the electrons are pulled more towards the oxygen atom. Since the molecule is not linear (due to lone - pair repulsion), the bond dipoles (from the polar \(O - H\) bonds) do not cancel out. So, the water molecule has a net dipole moment, making it a polar molecule.
• Question 18:
• Intramolecular bonds: These are the bonds within a molecule (e.g., covalent, ionic, metallic bonds). They involve the sharing or transfer of electrons between atoms to form the molecule. For example, in \(H_2O\), the \(O - H\) covalent bonds are intramolecular.
• Intermolecular bonds: These are the forces between molecules (e.g., hydrogen bonds, van der Waals forces). They are much weaker than intramolecular bonds. For example, the hydrogen bonds between water molecules are intermolecular.
• Chemical properties: Intramolecular bonds are responsible for the chemical properties of a molecule. Chemical reactions involve the breaking and forming of intramolecular bonds. For example, when water decomposes (\(2H_2O

ightarrow2H_2 + O_2\)), the \(O - H\) (intramolecular) bonds are broken.

Answer:

• Question 17: The oxygen atom in \(H_2O\) has two lone pairs. Lone - pair repulsion causes a bent shape. Oxygen is more electronegative than hydrogen. Bond dipoles in the non - linear \(H_2O\) molecule do not cancel, giving it a net dipole moment (polar molecule).
• Question 18: Intramolecular bonds (e.g., covalent, ionic) are within a molecule (electron sharing/transfer). Intermolecular bonds (e.g., hydrogen bonds) are between molecules (weak forces). Intramolecular bonds are responsible for chemical properties (involve in bond breaking/forming in reactions).