## The Structure of a Water Molecule [block_3] 1. A water molecule consists of **one** oxygen atom and **two** hydrogen atoms bonded together by **covalent** bonds. 2. **Covalent** **bonds** form when atoms **share** electrons. 3. However, in water, the sharing is **unequal** because oxygen is **more** **electronegative **than hydrogen. ![](https://cdn.sanity.io/images/w7j7fz60/production/9d41facd780cc7933480ddd8ce423f13dc9039ec-1690x786.png) **Electronegativity** is an atom's ability to **attract** electrons in a bond. ## Polarity: Unequal Charge Distribution [ae961e22d8be] 1. Because oxygen pulls electrons closer: 1. The **oxygen atom** develops a **partial negative charge (δ−)**. 2. The **hydrogen atoms** develop **partial positive charges (δ+)**. 2. This uneven charge distribution makes water a **polar molecule, **it has a positive end (hydrogen side) and a negative end (oxygen side). ### Polarity Enables Hydrogen Bonding [88c286840696] 1. This polarity is what allows hydrogen bonds to form between water molecules: 1. The **δ+ hydrogen** of one molecule is electrostatically attracted to the **δ− oxygen** of a neighboring molecules. 2. Because opposite charges attract, these polar regions create weak intermolecular attractions. 3. These attractions are **hydrogen bonds**. [{"_key":"145374f98bd8","_type":"block","asset":null,"children":[{"_key":"cb880763ae0a","_type":"span","markDefs":[],"marks":[],"text":"Although a single hydrogen bond is weak, water molecules are small and numerous, allowing for a "},{"_key":"d57edfe44ae4","_type":"span","markDefs":[],"marks":["strong"],"text":"dense network of these bonds"},{"_key":"63bfc8b27760","_type":"span","markDefs":[],"marks":[],"text":". "}],"markDefs":[],"style":"normal"}] [{"_key":"1a8a9b580ac7","_type":"block","asset":null,"children":[{"_key":"f9318e6e50390","_type":"span","marks":[],"text":"Polarity from unequal electron sharing → partial charges → electrostatic attraction between molecules → hydrogen bonding."}],"markDefs":[],"style":"normal"}] [{"_key":"ad13fa932eb3","_type":"block","asset":null,"children":[{"_key":"6dad053c787f","_type":"span","markDefs":[],"marks":[],"text":"Think of a game of tug-of-war between two players of unequal strength. "}],"level":1,"listItem":"bullet","markDefs":[],"style":"normal"},{"_key":"cbfa7260a17e","_type":"block","asset":null,"children":[{"_key":"a772a8e78a2f","_type":"span","markDefs":[],"marks":[],"text":"The stronger player pulls the rope closer to their side."}],"level":1,"listItem":"bullet","markDefs":[],"style":"normal"}] ## How to Draw a Water Molecule [0ce8478aaa17] > To show the structure and polarity of water: 1. **Draw the Atoms**: 1. Place **one oxygen atom** (O) in the center. 2. Add **two hydrogen atoms** (H) on either side, positioned at an angle of approximately **104.5°** to each other, reflecting the molecule's bent shape. 2. **Show the Bonds**: 1. Draw a single covalent bond (-) between each hydrogen atom and the oxygen atom. These represent shared electrons. 3. **Indicate Partial Charges**: 1. Label the oxygen atom with a partial negative charge (**δ⁻**) because it is more electronegative and pulls shared electrons closer. 2. Label each hydrogen atom with a partial positive charge (**δ⁺**) because electrons are drawn away from them. [{"_key":"259301092960","_type":"block","asset":null,"children":[{"_key":"238b89f8761c0","_type":"span","marks":[],"text":"Always include partial charges (δ+ and δ−) when drawing water molecules to show polarity."}],"markDefs":[],"style":"normal"}] [{"_key":"024e232de770","_type":"block","asset":null,"children":[{"_key":"d827add2d3c70","_type":"span","marks":[],"text":"What is the chemical formula for water?"}],"level":1,"listItem":"bullet","markDefs":[],"style":"normal"},{"_key":"d5962a2fb45d","_type":"block","asset":null,"children":[{"_key":"2a417c637816","_type":"span","marks":[],"text":"What type of bond connects hydrogen and oxygen within a water molecule?"}],"level":1,"listItem":"bullet","markDefs":[],"style":"normal"},{"_key":"07b9e15289dc","_type":"block","asset":null,"children":[{"_key":"01b37a767965","_type":"span","marks":[],"text":"What is electronegativity?"}],"level":1,"listItem":"bullet","markDefs":[],"style":"normal"},{"_key":"d7734d0df757","_type":"block","asset":null,"children":[{"_key":"67103d17fb15","_type":"span","marks":[],"text":"Why does oxygen have a partial negative charge in water?"}],"level":1,"listItem":"bullet","markDefs":[],"style":"normal"},{"_key":"590117481ba0","_type":"block","asset":null,"children":[{"_key":"114131149637","_type":"span","marks":[],"text":"Why do hydrogen atoms have partial positive charges in water?"}],"level":1,"listItem":"bullet","markDefs":[],"style":"normal"},{"_key":"3b7d09df7739","_type":"block","asset":null,"children":[{"_key":"93f984477067","_type":"span","marks":[],"text":"What does it mean for a molecule to be polar?"}],"level":1,"listItem":"bullet","markDefs":[],"style":"normal"},{"_key":"325df29ed9c7","_type":"block","asset":null,"children":[{"_key":"eb090af2737d","_type":"span","marks":[],"text":"How does polarity lead to hydrogen bonding between water molecules?"}],"level":1,"listItem":"bullet","markDefs":[],"style":"normal"},{"_key":"5a6263db6fce","_type":"block","asset":null,"children":[{"_key":"e207547dad44","_type":"span","marks":[],"text":"Draw a water molecule showing its bent shape and partial charges."}],"level":1,"listItem":"bullet","markDefs":[],"style":"normal"},{"_key":"7f3230e126dc","_type":"block","asset":null,"children":[{"_key":"23899a78cd89","_type":"span","marks":[],"text":"What is a hydrogen bond?"}],"level":1,"listItem":"bullet","markDefs":[],"style":"normal"},{"_key":"f46a06f7b965","_type":"block","asset":null,"children":[{"_key":"82e0fb592474","_type":"span","marks":[],"text":"Between which atoms does a hydrogen bond form in water?"}],"level":1,"listItem":"bullet","markDefs":[],"style":"normal"}]