2.2a Fundamentals of Chemistry

Summary

In this module on physiology, the instructor explains why understanding chemistry is crucial for grasping bodily functions. The lesson covers the composition of the human body by elements, emphasizing key ones like oxygen, carbon, hydrogen, and nitrogen. It introduces basic atomic structure, explaining protons, neutrons, and electrons, with a focus on electron shells and valence electrons, which determine how atoms bond. The periodic table is discussed, highlighting the importance of elements like calcium and sodium in physiological processes. The lesson wraps up with a quick quiz on valence electrons for various elements.

Takeaways

• 🧪 The module starts with the basics of chemistry because understanding the chemical properties of molecules and elements is essential for learning about physiology.
• 🌍 Oxygen is the most abundant element in the human body, making up nearly two-thirds of its composition, followed by carbon, hydrogen, and nitrogen.
• ⚛️ Elements are the simplest units of matter and cannot be broken down into smaller parts under normal circumstances (excluding nuclear fusion).
• 🧬 Atoms combine to form compounds, which are substances made up of two or more elements joined through chemical bonds.
• 🔬 Atoms consist of protons (positive charge), neutrons (neutral charge), and electrons (negative charge), with protons and neutrons forming the nucleus.
• ⚖️ The periodic table includes key information such as the atomic number (number of protons, neutrons, and electrons) and atomic weight (mass of one mole).
• 🔋 Electrons orbit the nucleus in specific regions called electron shells, and the outermost shell (valence shell) determines how an atom bonds with others.
• 🔄 Valence electrons, located in the outermost shell, play a crucial role in bonding properties, as seen in the sodium atom example.
• 💡 A quick overview of elements and their valence electrons includes examples such as hydrogen (1 valence electron), helium (2), carbon (4), and neon (8).
• 📊 Elements like calcium and iron will be essential to discussions throughout the semester, with calcium being particularly significant in the course.

Q & A

Why is chemistry important in a physiology class?

Many physiological processes in the human body are determined by the chemical properties of molecules and elements, making it essential to understand chemistry before diving into these processes.

What are the most abundant elements in the human body?

Oxygen, carbon, hydrogen, and nitrogen are the most abundant elements in the human body, with oxygen making up nearly two-thirds of all elements.

What are trace elements, and what is their role?

Trace elements, such as boron, chromium, and copper, exist in small amounts but play important roles as catalysts for chemical reactions in the body.

What is an element, and why is it important in chemistry?

An element is the simplest unit of matter that cannot be broken down into smaller parts. It is important in chemistry because elements combine to form compounds, which are the basis of chemical reactions.

What is the difference between an atom and an element?

An element is a type of matter, while an atom is the smallest quantity of that element which retains its unique properties.

What are the three types of atomic particles that make up an atom?

Atoms are made up of protons (positive charge), neutrons (neutral charge), and electrons (negative charge).

What is the significance of the atomic number on the periodic table?

The atomic number represents the number of protons in an element, and it also corresponds to the number of electrons in a neutral atom.

What is an electron shell, and why is it important in bonding?

An electron shell is a layer of electrons surrounding an atom’s nucleus at distinct energy levels. The arrangement of electrons in these shells, particularly in the outermost shell (valence electrons), determines how an element bonds with others.

What is valency, and why is it important in chemistry?

Valency refers to the number of electrons in the outermost electron shell of an atom, which determines how that atom can bond with other atoms.

How can we determine the number of valence electrons for elements like hydrogen, helium, carbon, and neon?

For hydrogen, there is one valence electron. Helium has two, filling its first shell. Carbon has four valence electrons, and neon has eight, filling its second shell.