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.

Outlines

00:00

🧪 Introduction to Chemistry for Physiology

The speaker begins by addressing why chemistry is important in a physiology course, explaining that understanding molecular and elemental interactions is crucial for grasping physiological processes. The human body's composition is highlighted, with oxygen, carbon, hydrogen, and nitrogen being key elements, followed by inorganic elements like calcium and phosphorus. Trace elements, like boron and fluorine, serve as catalysts in reactions. The concept of elements as the smallest unit of matter is introduced, with a note on exceptions such as nuclear fusion. The transition into compounds, formed by chemical bonds between elements, sets the stage for further exploration of atomic structure.

05:01

🧬 Understanding Atoms and Atomic Structure

The discussion continues by defining an atom as the smallest quantity of an element, retaining its unique properties. The structure of atoms is explored, explaining that atoms consist of protons (positive charge), neutrons (neutral charge), and electrons (negative charge). The planetary model of the atom is introduced, using helium as an example with two protons and two neutrons in the nucleus. The focus shifts to the periodic table, specifically carbon, explaining the atomic number (number of protons, neutrons, and electrons) and atomic weight. The concept of a mole in chemistry is briefly reviewed, followed by an introduction to valency, the electron configuration determining how atoms bond.

⚛️ Electron Shells and Bonding Properties

The third section delves deeper into electron shells, which dictate how atoms bond with others. A crash course on electron shells is presented, explaining that the first shell holds two electrons, the second holds eight, and the third shell begins to fill after that. Sodium is used as an example with 11 electrons, filling the first two shells and leaving one valence electron in the third. The valence electron's role in determining bonding properties is emphasized. The section concludes by reviewing four elements (hydrogen, helium, carbon, neon) and identifying their valence electrons based on their atomic structure.

Keywords

💡Element

An element is the simplest unit of matter that cannot be broken down into smaller parts without losing its chemical properties. The video explains that elements make up the human body, with oxygen, carbon, hydrogen, and nitrogen being key examples. These elements are crucial for understanding how chemical processes in the body work, tying directly to the video's focus on physiology.

💡Atom

An atom is defined as the smallest unit of an element that retains the properties of that element. In the video, atoms are discussed in the context of their role in physiology and chemistry, specifically as the building blocks of elements and molecules. For example, an atom of hydrogen is used to describe the fundamental structure of matter.

💡Proton

Protons are positively charged particles found within the nucleus of an atom. The video mentions protons when describing the structure of atoms, using a helium atom model as an example. Protons, along with neutrons and electrons, form the basis of atomic structure, which is crucial for understanding how elements behave in physiological processes.

💡Neutron

Neutrons are neutrally charged particles located in the nucleus of an atom. In the video, neutrons are introduced when discussing atomic structure, specifically in relation to the helium atom model. Neutrons, along with protons, contribute to the atomic mass and play a role in the stability of the atom.

💡Electron

Electrons are negatively charged particles that orbit the nucleus of an atom. The video emphasizes the role of electrons in determining how atoms bond with each other, specifically focusing on their arrangement in electron shells. For example, the video explains how the number of electrons in the outermost shell (valence electrons) influences bonding behavior.

💡Valence Electron

Valence electrons are the electrons in the outermost shell of an atom, which determine its chemical bonding properties. In the video, valence electrons are highlighted when discussing elements like sodium, where the outermost electron dictates how the atom can bond with others, which is fundamental to understanding molecular interactions in physiology.

💡Periodic Table

The periodic table is a chart that organizes elements based on their atomic number and properties. In the video, the periodic table is referenced when explaining elements like carbon and calcium, focusing on their importance in physiological processes. The video highlights the atomic number and atomic weight as key characteristics for understanding an element’s properties.

💡Atomic Number

The atomic number represents the number of protons in an atom of an element. In the video, the atomic number is explained in the context of how it helps identify elements, such as carbon, which has an atomic number of 6. This number also indirectly indicates the number of electrons in a neutral atom, which is crucial for understanding chemical behavior.

💡Electron Shell

Electron shells are regions around the nucleus of an atom where electrons are likely to be found. The video explains that these shells have distinct energy levels, and the number of electrons in the outer shell (valency) determines the atom’s bonding capacity. The concept is demonstrated using the sodium atom model, which has one electron in its outermost shell.

💡Molecule

A molecule is formed when two or more atoms are joined together through chemical bonds. In the video, molecules are discussed as compounds of elements that are relevant in physiological processes. The interaction of elements, such as carbon and oxygen, in forming molecules like carbon dioxide, helps illustrate how chemical properties impact bodily functions.

Highlights

Introduction to the fundamentals of chemistry in a physiology class.

The chemical properties of molecules and elements influence physiological processes in the human body.

The human body is primarily composed of oxygen, followed by carbon, hydrogen, and nitrogen.

Inorganic elements such as calcium, phosphorus, and potassium play crucial roles in physiology.

Trace elements like boron, chromium, cobalt, and copper act as catalysts for chemical reactions.

Elements are the simplest unit of matter, with some exceptions due to nuclear fusion.

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

Protons and neutrons are located in the nucleus, while electrons orbit in shells around it.

The periodic table shows the atomic number and atomic weight, with a focus on up to calcium for the course.

A mole equals 6.02 x 10^23 atoms, an important concept in chemistry.

Electron shells determine how atoms bond, focusing on outer shell electrons (valence electrons).

Valency is a key concept in determining how atoms bond with others.

The first electron shell holds two electrons, the second can hold eight.

Sodium's electron configuration with 11 electrons is an example of how valency works.

Examples of valence electrons for elements: hydrogen (1), helium (2), carbon (4), and neon (8).

Transcripts

Welcome back folks. So in this module we're going  to start off with the fundamentals of chemistry.  

So some of you might be asking, "Okay this is  a physiology class — why do we have to get into  

chemistry?" Well it turns out many of the processes  in the human body are determined by the chemical  

properties of those molecules and elements,  so it makes sense — before we jump into any  

serious physiology processes, we have to learn  about how these atoms and elements interact  

at the molecular level. So let's go ahead and  start off with the composition of the human body.  

So as you can see on your screen  right here, specifically at the table,  

you can see what percentage each element  makes up in the human body. So some of the  

most relevant ones that we'll be discussing  throughout the whole entire semester include  

oxygen, which makes up nearly two-thirds of all  elements in the human body and that's followed by  

carbon, which makes about 1/6 of the total elements  in the body. We also have a notable amount of  

hydrogen and nitrogen, followed by some inorganic  elements such as calcium, phosphorus, and potassium.  

So at the bottom of the table you'll notice  that there will be some trace elements such as  

boron, chromium, cobalt, copper, fluorine, etc. and so  these are largely there as catalysts for chemical  

reactions to occur. So when I say "element", this is  the simplest unit of matter that cannot be broken  

down into smaller parts. There's an asterisk there  just because there are some technicalities to this  

such as nuclear fusion but we won't really jump  into much detail about that. So for all intents  

and purposes, elements are, for us, the smallest  unit of matter. So in nature, elements rarely occur  

by themselves but instead they've combined to form  compounds. And so we define compounds as substances  

composed of two or more elements joined through  chemical bonds and what we'll see in a moment  

is that the chemical properties of each element  determines what type of bonds can be formed by  

that element. So diving right in, let's go ahead and  review what an atom is and what is it made up of.  

So an atom is defined as the smallest quantity of  an element that retains unique properties of that  

element. So put in another way, an atom of hydrogen  is considered the smallest unit of hydrogen that  

can exist. As you might be able to guess, atoms are  unfathomably small. So these atoms are composed of  

even smaller atomic particles and there's three  types. So we have protons, which have a positive  

charge, neutrons which have a neutral charge, and  electrons that have a negative charge. And as you  

can see on our helium model, right here — so notice  in the planetary model there is a nucleus in the  

center and surrounding it are electrons within the  nucleus. You can see it's made up of two protons  

and two neutrons. So since we're going to be  talking about all these different elements, I think  

it's worth reviewing some of the key points of  the periodic table of elements. So let's go ahead  

and use carbon as an example. So carbon is the  sixth element on the periodic table of elements  

and there are two particular numbers that I think  you should be aware of. So the first one is this  

number, the atomic number, and it indicates the  number of protons neutrons and electrons for that  

atom. Next you'll notice that there is this number  right here, which corresponds to the atomic weight  

or the mass in one mole of carbon. And  so just a quick review from chemistry  

a mole is equal to 6.02 times 10 to  the 23rd atoms and so for this class  

— and so for this class, you should be aware — so  for this course you should be generally aware  

of the chemical properties of these elements...  about up to calcium. We're actually going to be  

talking about calcium quite a bit in this course.  Some other elements that might be past calcium  

include iron, when we talk about hemoglobin but  that's not quite as important as everything before  

our 20th element calcium. So when talking about  elements it's important to focus on the electrons  

since they determine how an element can bond  to other elements. So unlike some of the images  

of atoms that I've shown on the previous screen  and the one that you see of sodium right here,  

electrons don't actually orbit the nucleus in  a perfect circle instead they stay within these  

particular regions of space called electron shells.  And an electron shell is a layer of electrons  

that surround the nucleus at distinct  energy levels and we call this valency  

and this valency determines how that atom can bond  with other atoms. And I just want to point out that  

specifically it's electrons that occupy so — specifically it's electrons that occupy the outer  

electron shell. So we're going to do a very  quick crash course on electron shells. If you  

need a little bit more in-depth explanation about  this, you could take a look at the video that I am  

linking in the upper right corner. Otherwise, let's  go ahead and start with this quick explanation.  

So like I said before, electron shells can  accommodate a certain number of electrons and each  

electron shell has space for a specific number of  electrons. So in the first layer that we see here,  

we see that the first electron shell can  accommodate two electrons. After that, we move  

on to the next electron shell. So our second  electron shell, which can accommodate eight  

electrons — after all those eight electrons occupy  the second shell, then we move on to our third  

and as we can see there's only one electron  occupying that third electron shell. And this  

corresponds to the atomic number of sodium, 11,  which which means that there are 11 electrons. We  

have two in the first shell we have eight in the  second shell and then one more to get that number  

11. So this outermost electron is what we call a  valence electron, because it occupies the outermost  

shell and it determines the bonding properties  of our sodium ion, which we'll discuss when we  

talk about ionic bonding. So based on what we've  just learned, we have four different elements here  

starting with the one right here, we have hydrogen,  helium, carbon, and neon. So for each of these  

go ahead and answer the question of, "How many  valence electrons do each of these elements  

have?" Okay and so for hydrogen this one's easy  since we're on the first shell we have one single  

electron, which is our valence electron so it's  one. And helium, the second atomic element has two  

electrons, so those two electrons will fill the  first electron shell — so we have a valency of two.  

For carbon, which is our sixth element, those  first two electrons will occupy that first shell  

and then the next four electrons will occupy that  second shell which gives us a valency of four.  

And then neon the tenth element has two — its first  two electrons occupy that first electron shell and  

then the remaining eight will occupy its outermost  shell so we have eight valence electrons here.