University:
York University
Course:
SC/BIOL 2021 | Cell Biology
Academic year:

2023
Views:

173

Pages:

3
Author:

Nick T.

Header: Types of Covalent Bonds Section 1: Electrons Shared 'equally' Subheader: Non-Polar Covalent Bond Note: Can be single like H₂, double O₂, or even triple, depending on the amount of electrons shared. Covalent Bonds: sharing valence electrons Diagram 1: 2 hydrogen atoms Diagram 2: 2 oxygen atoms Single bond: H-H Double bond: O=O Text: Both are examples of non-polar covalent bonds. Section 2: Electrons are NOT shared equally Subheader: Polar Covalent Bond Note: One of the atoms has a stronger pull on the electrons than the other. Pull on electrons: Electronegativity Example: H₂O Text: Oxygen has the highest electronegativity than any other atom. Diagram 3: H₂O molecule with partial charges Text: Water is a polar molecule. Charge is unevenly distributed. One part slightly negative, two parts slightly positive. Header: Non-Covalent Bonds Subheader: Ionization and Ionic Bonds Text: sodium atom (Na), chlorine atom (Cl), sodium ion (Na+), chloride ion (Cl-), sodium chloride (NaCl) Note: + balances with the - Text: Water is the most abundant molecule in biological organisms. Text: Human body is 70% water. Text: Water as a solvent can dissolve more types of molecules than other known molecules. It's the universal solvent. Text: The polarity of water is key to its role in biology. Subheader: Hydrogen Bonding Text: Electrical attraction between electronegative atom and partially positive hydrogen. Visual Elements: Diagram 1: Three circles representing sodium and chlorine atoms, sodium ion, and chloride ion. Diagram 2: A sphere representing sodium chloride. Diagram 3: A water molecule with partial charges. Arrows: Arrows indicating the transfer of electrons in the first diagram. Labels: Labels for the different atoms, ions, and molecules. Image Analysis Textual Content: Header: Water as a Solvent Text: Polar compound: e.g. NaCl Text: Non Polar: e.g. Oil in Water Text: Becomes electrically neutral when partially negative oxygen interacts with partially positive Na and + H interacts with -Cl Text: Hydrophobic - No affinity for water Text: Hydrophilic - Affinity for water Text: H-C carbon & hydrogen have equal electronegativity. Text: All of water's striking properties are a direct result of its ability to form H-bonds. Header: Bond length vs. Strength Text: The longer the bond, the weaker the bond. Text: The shorter the bond, the stronger the bond. Table: | BOND TYPE | LENGTH (nm) | STRENGTH IN kcal/mole IN VACUUM | STRENGTH IN kcal/mole IN WATER | |---|---|---|---| | Covalent | 0.15 | 90 (377) | 90 (377) | | Noncovalent: hydrogen bond* | 0.30 | 4 (16.7) | 1 (4.2) | | Noncovalent: van der Waals attraction (per atom) | 0.35 | 0.1 (0.4) | 0.1 (0.4) | Note: *An ionic bond is an electrostatic attraction between two fully charged atoms. Values in parentheses are kJ/mole: 1 calorie = 4.184 joules.