1.3.1 Composition and Structure

• A water molecule consists of two hydrogen atoms and one oxygen
• What type of bonds are formed between hydrogen and oxygen in water?

  Covalent
• What is the bond angle in a water molecule?

  104.5°
• The bond angle in a water molecule is approximately 104.5°
• Steps to illustrate the V-shape structure of water using a graph

  1️⃣ Oxygen atom forms covalent bonds with two hydrogen atoms

  2️⃣ Lone pairs on oxygen repel bonding pairs

  3️⃣ Bond angle of 104.5° is created

  4️⃣ Molecular geometry becomes bent or angular
• What type of charge is found on the hydrogen atoms in water?

  Partial positive (δ+)
• The chemical formula H2O indicates that a water molecule is composed of two hydrogen atoms and one oxygen atom.

  True
• In a water molecule, oxygen forms polar covalent bonds with hydrogen
• Why is the covalent bond in water polar?

  Oxygen is more electronegative
• Match the feature of water with its description:

  Shape ↔️ V-shape

  Bond Angle ↔️ 104.5°

  Lone Pairs ↔️ Two on oxygen
• The bond angle in water is exactly 104.5 degrees.


  True
• Why does oxygen in water have a partial negative charge?

  It is more electronegative
• Steps to illustrate hydrogen bonding in water using a graph

  1️⃣ Oxygen in one water molecule forms a covalent bond with hydrogen

  2️⃣ Partially positive hydrogen is attracted to partially negative oxygen

  3️⃣ Hydrogen bond forms between molecules
• Hydrogen bonds in water are stronger than covalent bonds.

  False
• Hydrogen bonds form between the partially positive hydrogen and the partially negative oxygen
• What is the effect of hydrogen bonding on water's surface tension?

  Increases surface tension
• Which atoms in water form hydrogen bonds with other water molecules?

  Partially positive hydrogen
• What is the chemical formula of water?

  H2O
• The unique composition of water gives it its chemical properties and role in biological systems.


  True
• Oxygen is more electronegative than hydrogen, creating a polar covalent bond in water.


  True
• The water molecule has a V-shape
• The molecular shape of water is linear.

  False
• The molecular geometry of water is described as bent or angular
• Match the property of water with its description:

  Electronegativity Difference ↔️ Oxygen > Hydrogen

  Charge Distribution ↔️ Oxygen δ-, Hydrogen δ+
• Hydrogen bonds in water increase its boiling point.


  True
• Water molecules are polar because oxygen is more electronegative