Notes on Chemical Bonding, Polarity, and Reactions

Types of Chemical Compounds:
- Chemical compounds are divided into two main categories based on the interactions of their electrons:
  - Ionic Compounds / Ionic Bonds:
    - Formed from the combination of a Metal and a Non-metal.
    - Involves the complete transfer or stealing of electrons from one atom to another.
    - Consists of charged particles:
      - Cation: A positively charged ion ( $+$ , formed when an atom loses electrons).
      - Anion: A negatively charged ion ( $-$ , formed when an atom gains electrons).
    - Overall Charge: Ionic compounds have an overall net zero charge because the total positive charges of the cations balance the total negative charges of the anions.
    - Example: Table salt / water salt ( $NaCl$ ).
  - Molecular-Covalent Compounds / Covalent Bonds:
    - Formed between a Non-metal and a Non-metal.
    - Involves the sharing of electrons between atoms rather than electron transfer.
Periodic Table Trends and Ion Formation:
- Metals:
  - Located on the left side of the periodic table.
  - Less electronegative than non-metals.
  - Tend to lose electrons to become positively charged cations ( $+$ ).
- Non-metals:
  - Located on the right side of the periodic table.
  - More electronegative than metals.
  - Tend to gain electrons during chemical reactions to become negatively charged anions ( $-$ ).

Electronegativity:
- Electronegativity is the measure of an atom's ability to attract shared electrons in a bond.
- Oxygen is significantly more electronegative than carbon.
Subtypes of Covalent Bonds:
- Polar Covalent Bonds:
  - Occur when electrons are shared unequally between two non-metal atoms.
  - Unequal sharing creates partial electrical charges across the bond or molecule:
    - $\delta^+$ (partial positive charge): Assigned to the less electronegative atom.
    - $\delta^-$ (partial negative charge): Assigned to the more electronegative atom.
  - Example: Water ( $H_2O$ ).
    - Water has a bent molecular structure.
    - The oxygen atom is more electronegative and pulls shared electrons closer, gaining a partial negative charge ( $\delta^-$ ), while hydrogen atoms bear partial positive charges ( $\delta^+$ ).
- Nonpolar Covalent Bonds:
  - Occur when electrons are shared equally between atoms.
  - Results in no partial charges across the molecule.
  - Examples:
    - Any element bonded to itself (e.g., diatomic oxygen, $O_2$ ).
    - Carbon-Hydrogen bonds (e.g., methane, $CH_4$ ).

The "Like Dissolves Like" Principle:
- Polar substances dissolve other polar substances.
- Nonpolar substances dissolve other nonpolar substances.
- Polar and nonpolar substances cannot dissolve in each other.
Solubility Testing for Polarity:
- Water is a polar molecule.
- To determine if a substance is polar or nonpolar, test its behavior in water:
  - If it dissolves in water, it is polar (or ionic).
  - If it does not dissolve in water, it is nonpolar.
Biological Relevance:
- Living organisms are composed of cells.
- Organic life is carbon-based, with biological matter comprising $50\%$ to $90\%$ carbon-based/organic materials.
- The human body is primarily made of water, making liquid polarity central to bodily functions.
- Electrolytes: Solutes that dissolve in the body's internal water environment to yield essential free ions.

Real Chemical Bonds:
- Defined as force interactions that occur within a single molecule or compound (intramolecular forces).
- Examples include covalent bonds and ionic bonds.
Pseudo Bonds and Hydrogen Bonding:
- The prefix PSEUDO- means false, fake, or not genuine.
- A hydrogen bond is considered a