Introduction to Chemistry in Biology

The Periodic Table and Elements

• The periodic table contains approximately $118$ different elements.
• This table is dynamic, with new elements potentially being discovered, a process that could lead to significant scientific recognition.
• All living organisms, from bacteria to worms and human beings, are fundamentally composed of these elements.
• While specific elements make up the bulk of living matter, many other elements are present in smaller quantities.
• From a chemical perspective, elements are largely synonymous with atoms.
• Atoms are the foundational building blocks that aggregate to form molecules, which in turn form organelles, and ultimately, cells.

Atomic Structure and Properties

• Question: What determines the properties of a compound?
• Compounds are formed from atoms.
• Atoms themselves can be further broken down into three subatomic components:
  • Protons: Possess a positive electrical charge $(+)$. Located in the atom's nucleus.
  • Neutrons: Are electrically neutral (no charge). Also located in the atom's nucleus.
  • Electrons: Possess a negative electrical charge $( - )$. They orbit the nucleus in distinct