Introduction to Chemistry in Health Sciences

Overview

This guide introduces foundational chemistry concepts essential for understanding biological processes in health and psychology. Mastery of these topics supports comprehension of drug actions, metabolism, cellular respiration, and energy flow in living systems.

Anatomy of the Atom

Subatomic Particles

An atom is the smallest unit of matter, composed of a central nucleus and surrounding electrons.

• Protons: Positively charged particles found in the nucleus. The number of protons determines the atomic number and the identity of the element.

• Neutrons: Neutral particles in the nucleus. The number of neutrons affects the atomic mass and creates isotopes when varied.

• Electrons: Negatively charged particles orbiting the nucleus. The number of electrons usually equals the number of protons in a neutral atom.

Atomic Number: Number of protons in the nucleus. Atomic Mass: Sum of protons and neutrons.

Example:

• Oxygen: Atomic number = 8, Atomic mass ≈ 16

Chemical Bonding and Molecular Formation

Types of Chemical Bonds

Chemical bonds form when atoms interact to achieve stability, resulting in molecules.

• Covalent Bonds: Atoms share electrons. If sharing is equal, the bond is nonpolar; if unequal, the bond is polar, creating partial charges.

• Ionic Bonds: Electrons are transferred from one atom to another, creating charged ions that attract each other.

• Hydrogen Bonds: Weak attractions between polar molecules, important in water and biological molecules.

Example:

• Water (H2O): Polar covalent bonds create partial charges, allowing hydrogen bonding between molecules.

Atoms vs. Ions and Redox Reactions

Atoms and Ions

An atom becomes an ion when it gains or loses electrons, resulting in a net charge.

• Cation: Positively charged ion (loss of electrons).

• Anion: Negatively charged ion (gain of electrons).

Redox (Reduction-Oxidation) Reactions

Redox reactions involve the transfer of electrons between substances.

• Oxidation: Loss of electrons (becomes more positive).

• Reduction: Gain of electrons (becomes more negative).

Example:

• Sodium Chloride Formation: Sodium (Na) donates an electron to chlorine (Cl), forming Na+ and Cl- ions, which bond ionically.

Types of Chemical Reactions

Classification of Reactions

Chemical reactions involve the breaking and forming of bonds to create new substances.

• Synthesis: Two or more reactants combine to form a larger product.

• Decomposition: A compound breaks down into simpler substances.

• Single Displacement: One element replaces another in a compound.

• Double Displacement: Exchange of ions between two compounds.

Example:

• Glucose phosphorylation: Glucose + ATP → Glucose-6-phosphate + ADP

Energy in Chemical Reactions

Types of Energy

Energy is the capacity to do work or cause change. It exists in various forms:

• Kinetic Energy: Energy of motion.

• Potential Energy: Stored energy due to position or structure.

First Law of Thermodynamics

Energy cannot be created or destroyed, only transformed from one form to another.

Bond Energy and Energy Flow

Energy is required to break chemical bonds and released when new bonds form.

• Exergonic Reaction: Releases energy (e.g., cellular respiration).

• Endergonic Reaction: Absorbs energy (e.g., photosynthesis).

Example Equations:

• Cellular Respiration:

• Photosynthesis:

Summary Table: Types of Chemical Reactions

Clinical and Psychological Relevance

Applications

• Understanding chemical principles is essential for interpreting drug actions, metabolism, and physiological responses.

• Energy transformations underlie cellular processes such as ATP production and neurotransmitter activity.

• Knowledge of ions and chemical reactions informs fluid and electrolyte balance, crucial in clinical care.

Additional info: These chemistry concepts form the foundation for advanced study in physiology, pharmacology, and psychological processes involving neurotransmitters and cellular signaling.