Oxygen, Carbon, and Nitrogen OH MY

I did not mean to leave out these super important non-metals in my overview of the periodic table. Therefore based on the feedback I received from Kyla I am going to take a look at all three. All three of these non-metals are quite abundant and easily found in nature and they commonly form covalent bonds. Below is a brief look at each element along with the corresponding Periodic Table of Videos video explanation.

Oxygen: 

This element is perhaps one of the best known to the general public. It is found in group 16 of the periodic table and is highly reactive. Oxygen is the third most abundant element found in the sun and is an important part of the carbon-nitrogen cycle. 21% of the atmosphere is oxygen and about 2/3rds of the human body is composed of this element. There is no doubt that this element is extremely important to us.

Nitrogen: 

This element is found in group 15 of the periodic table and makes up around 78% of the earth's air by volume. It is found in all living systems within biological compounds. When organic matter decomposes you have the formation of sodium nitrate and potassium nitrate these compounds are part of the nitrogen cycle which is extremely important for living organisms. Nitrogen is crucial to life and is a component of all proteins.

Carbon:

Carbon is found in group 14 of the periodic table and is found free in nature as, graphite, diamond, and fullerines. Carbon is also found in the atmosphere within carbon dioxide. Carbon like oxygen and nitrogen it can form a large number of compounds due to the number of valence electrons in their outer shells. Carbon itself is part of close to ten million compounds.

This is only just a very brief look at these three important non-metals. No doubt they are extremely important in the world of chemistry and just having a background on their presence on earth is important. This once again links chemistry and biology together and interconnects my strengths with my weaknesses. Thanks again to Kyla for her feedback and guidance in this matter. 

Sharing My New Found Knowledge

One of the things I wanted to get out of this process was the ability to confidently discuss atomic theory and how the periodic table is organized with an expert in the chemistry field. One of my colleagues has a bachelor of science in chemistry and math and has an expansive knowledge in the area of chemistry. We sat down this afternoon and discussed what I had gained form the experience and she gave me the confidence that I know how to clearly explain the theories and processes I described in detail throughout this blog. My colleague sent me her thoughts on my understanding in an email and I have included this below.

"Great job Jenn. I remember our conversation before we started this process and you were so surprised at how many trends were within the periodic table. You came a long way. I really enjoyed how many different resources you used to draw your information from. I found myself doing the same thing for microbiology. We will have to remember ,when we become teachers, that students will need just as many resources to understand concepts as we did to learn these areas. I really enjoyed how you separated your concepts well into postings and made it so easy to follow. You gave a great history of how atomic theory came about, and used clear terminology. I also liked your post about new elements. A common misconception I came across during my chemistry practicums was student's thinking the chemical periodic table can't change. Your research shows how dedicated you were to this project and how committed you are to understanding different sciences. Have confidence in your understanding and knowledge of atomic theory and the periodic table of elements because it most defiantly came through in our conversation and in your blog

In one of your postings you talked about each of the groups and gave some examples and information on them. For group 14-16 you included it with group 13, even though there are many non-metals located within these groups. Maybe you can write a bit about the non-metal elements in groups 14-16 (Carbon, Nitrogen and Oxygen) since a lot of high school chemistry, and even most of my B.Sc in chemistry were geared towards these three elements. Other than that I am so pleased with the work you put into this learning assignment, and know how far you've come since the start!

Kyla Gillis"

This has been a wonderful learning experience and I have found the blogging very useful to aid in my rediscovery process. I could see using blogging in the future if only as a place to put my thoughts down. I look forward to taking part in many more self directed learning tasks as I grow as a science teacher. Here is a cool image of the periodic table made of cupcakes :)

Yummy!

The Periodic Table of Videos

As my final post in my rediscovery process I want to briefly provide some feedback on the following online resource. It is called the Periodic Table of Videos and was created by The University of Nottingham and video journalist Brady Haran. The site contains a video for all 118 elements on the periodic table. The videos consist of descriptions of the elements, stories, samples, and experiments. The sit also has other series of videos on the go including a molecular series and new stories along with videos from adventures outside the lab. I wanted to make a specific posting just on this resource because I believe it has great potential for any chemistry classroom, especially for a teacher who may not be as comfortable with the material as others. Below I have included the video that goes with the element Hydrogen. The video provides a mixture of explanation along with an exciting experiment with a balloon filled with hydrogen... you can just imagine what happens.

The second video that I want to share with you from this neat site is from their new molecular series. It is about toxins that tiny frogs, usually found in Latin America, produce as a protection mechanism. A very small amount of the toxins can kill a human by attacking the nervous system. The frogs are endangered but they have broken down the toxin into its compound parts and can create it synthetically.   I really liked this video because I can see using it in a biology class and again connects biology and chemistry.

The videos done for this site are put together so well and and are extremely informative and engaging. This would have to be my favourite resource that I came across during this process. I would bookmark it if I were you!

New Elements?

As the nature of science clearly shows new discoveries are always happening in the world of science. As I was looking into the periodic table I discovered that there are two new elements that are currently trying to become members of the elusive club. The names, flerovium (atomic symbol Fl) and livermorium (atomic symbol Lv) have been supplied to the International Union of Pure and Applied Chemistry who oversee the list of elements found in the periodic table. It is interesting to note that if you don't like the names you can voice your opinion until May of 2012 when they will get either the stamp of approval or thrown out.

Here is the article about the two new elements that was posted December 1st, 2012 in the New York Times for your own reading pleasure.

Names Proposed for 2 New Elements on Periodic Table

The great resource, The Periodic Table of Elements, also posted a video discussing these same new elements.

Cliques of the Periodic Table

 When Mendeleev began organizing the elements there were only 60 identified named elements. Now in the modern periodic table there are 112 named elements represented. These 112 elements are generally identified as either metals, nonmetals, or metalloids. 80% of the elements are metals (shiny elements that conduct heat and electricity well), 15% of the elements are nonmetals (poor conductors of heat and electricity), and the remaining elements are unique  in that that they share properties of metals and nonmetals called metalloids. These metalloids create a staircase shape in the periodic table as seen in the purple shaded area below.

Metals, Nonmetals, Metalloids

As was previously stated the periodic table is organized in both rows and columns. The columns are referred to as groups and indicate elements with similar chemical and physical properties. The modern periodic table consists of 18 of these cliques and we are going to take a closer look at each of these groups.

Periodic Table Groups

Group 1: Alkali Metals
Examples: lithium, sodium, potassium
Alkali Metals are highly reactive and not usually found freely in nature. They have only one valence electron and get their name from the highly alkaline substances, sodium hydroxide, they produce when reacting with water.

Group 2: Alkaline Earth Metals
Examples: magnesium, calcium, barium
Alkaline Earth Metals are less reactive than the group 1 metals and they are not usually found alone in nature. They have two valence electrons which they yield in chemical reactions. Common substances that contain Alkaline Earth Metals include seashells (calcium carbonate) and gemstones like aquamarine (beryllium).

Group 3: Lathanoids and Actinoids
Examples: actinium, uranium
This group includes shiny metals and radioactive elements. Lathanoids are abundant in the Earth's curst but are difficult to separate from their compounds while Actinoids are radioactive and are made in nuclear reactors. For of the Actinoids are found naturally however; actinium, thorium, protractinium, uranium.

Groups 4-12: Transition Metals
Examples: iron, nickel, gold, silver
Transition metals are all shiny metals and can be found naturally. They are however less reactive than groups 1 and 2.

Group 13 (some in 14-16): Metals
Examples: tin, lead, bismuth
Metals are harder and denser than those in groups 1 and 2 while they are softer and less dense than the transition metals. They can exist freely once refined but they are most often found as compounds in nature.

Group 17: Halogens
Examples: fluorine, bromine, iodine
Halogens are a group of similar non-metals. These elements are too reactive to occur freely in nature. The most characteristic chemical feature of the halogens is their ability to oxidize.

Group 18: Nobel Gases
Examples: helium, neon, xenon
Nobel gages are often called inert gases as well because they don't react with other elements. This is because their highest energy levels are full and they do not tend to share their valence electrons with other elements.

The Organizational Skills of Mendeleev

Although the evolution of the modern Periodic Table of Elements had many major contributions a Russian chemist Dmitri Mendeleev is credited with first trying to organize the chemical elements according to atomic weights  in 1869. He had predicted that the properties of the elements would change as the atomic weight increased. However Mendeleev discovered that these gradual changes changed suddenly at distinct steps or periods. Thus he grouped the elements in a table with both rows and columns. Mendeleev's discoveries led to the modern periodic table which we use today and is organized by atomic number.

The Periodic Table of Elements

The rows in a periodic table are called periods, and as you move right along a given period the chemical properties of the elements gradually change. The period number signifies the highest energy level an electron in that element occupies. The columns in the periodic table are called groups, and the elements in a given group share similar chemical and physical properties. a group of elements have identical valence electron configurations which allows them to behave in similar chemical fashion.

The Periodic Table of Elements - So Many Resources!

Upon a brief search in any search engine it is not difficult to find numerous web pages devoted to the famous Periodic Table of Elements. Before I provide an overview of some of the trends found in the Periodic Table I thought I would provide you with a list of my favourite online resources that I found.

1. Los Alamos National Laboratory - Periodic Table of Elements

2. Chemicool - Periodic Table of Elements

3. Royal Society of Chemistry - Visual Elements Periodic Table

4. Chemical Elements - An Interactive Periodic Table

5. Web Elements - Periodic Table

6. Visionlearning - Periodic Table of Elements

7. University of Nottingham - The Periodic Table of Videos

The internet provides numerous places to take an in depth look at each of the elements in the table and the trends found within the table. As a teacher it is wonderful to have resources so easily accessible. Learning has changed so much from when I was a student. I recall being in panic mode if I forgot my coloured photocopy of the Periodic Table when going to chemistry class. Now it is so easy to access the famous chemistry tool. I Bet there is even an app for that...

Well look at that there is an app for that. Take a look: Periodic Table of Elements App - ITunes

Discovery of the Atomic Nucleus

Here are two videos from a series of 15 videos created by the Science and Technology Facilities Council. Their YouTube site is full of useful videos that help explain many scientific concepts and ideas. These two videos take a look at the experiments Thomson and Rutherford used to discover their famous findings.

Video 2 of 15 - The Discovery of the Electron

Video 3 of 15 - The Discovery of the Atomic Nucleus

If the story interests you there are a 15 videos that deal with the idea of particle physics. It interests me that the history of Atomic Theory is relevant in both physics and chemistry. I am glad that I picked a topic that can be used in two subjects that I am not as familiar with. All science is connected and I have begun to see more of these connections through this learning process. Now it is time to move on to the Periodic Table of Elements. 

Side Note

I provided an in depth description of the history of Atomic Theory but think that it is important to include a short post on how atomic structure is connected to bonding. The Bohr diagram that I drew in my last post shows the arrangement of subatomic particles in atoms. The following are some key vocabulary that it is important to understand and use when discussing Atomic Theory:

Stable Octet = A energy shell that is full
Valence Shell = The outermost energy shell containing electrons
Valence Electrons = The electrons in the valence shell (these electrons are involved in bonding)
* When an atom forms a compound it acquires a full valence shell and becomes stable.

There are two basic types of compounds, ionic and covalent.

Ionic Compounds:
Atoms become electrically charged particles known as ions when they lose or gain electrons during bonding. An iconic compound consists of a positive ion and a negative ion. In ionic bonding at least one electron transfers from each atom of the metal ion to each atom of the non-metal ion. The metal ions lose their electrons and become positively charged ions called cations. Non-metal ions gain electrons becoming negatively charged ions called anions. Cl becomes an anion as it gains one electron becoming Cl 1-.

Covalent Compounds:
Only two non-metal atoms can bond covalently. In covalent bonding the atoms of two non-metals share electrons. Unpaired electrons from each atoms will pair together as a bonding pair creating a covalent bond.

Resources:

The following is a PDF of an exert from a textbook.

Atomic Theory and Bonding

Electron Shell Diagrams & Modern Atomic Theory

First of all I want to point out that I have created a great set of notes by creating this blog. If I do find myself teaching Science 9 in the near future I will be much more prepared to tackle this topic.

Following up on the Bohr-Rutherford model I am going to show you how to draw a electron shell diagram. For the purpose of this blog I am going to pick one element to use as an example. However the same steps can be used for any of the elements in the Periodic Table of Elements. The element I will be using is  Chlorine (Cl).

The first thing you need to know when preparing to draw an electron shell diagram is how many protons/electrons the element you are dealing with has. The atomic number of an element tells you the number of electrons and protons found in each atom. When looking at the periodic table of elements box below the atomic number can be found above the Cl. You can use the atomic mass to determine the number of neutrons in an atom of the element as the atomic mass is the number of protons and number of neutrons. The atomic mass can be seen in the image below under the Cl.

To start an electron shell diagram you need to draw the nucleus and indicate inside the nucleus the number of protons and neutrons in the atom.

Cl nucleus: Protons = 17, Neutrons = 18

Then you can draw the first energy level. Based on the atomic number we know that Cl will have 17 electrons. According to Bohr's theory the first energy level can only hold a maximum of two electrons so you put two electrons on the first energy level.

First Energy Level

You have 15 more electrons to include in the diagram so you must draw a second energy level. The second energy level can hold a maximum of 8 electrons so you can fill this energy level. 

Second Energy Level

You still have 7 more electrons and they will go in the third energy level.

Third Energy Level

The key rules to remember when drawing electron shell diagrams is that the first energy level holds 2 electrons, the second and third energy levels hold a maximum of 8, and the fourth energy level can hold up to 18 electrons. Also due to the nature of electrons wanting to be in the lowest energy level possible it is important that in your diagram that the energy levels are full before drawing a new energy level. These diagrams show you the number of valence electrons an element has and helps you identify how the element bonds. Will the element want to receive an electron or give up one? A general rule is that an atom wants to be in a state where their energy levels are full. So in the case of a Cl atom you would expect it to accept an electron to make the third energy level full with 8 electrons. The opposite is true for an element like sodium that has only one valence electron in the third energy level. Na wants to give up its electron so that it can reach a state where its' first two energy levels are full. These diagrams help provide a visual element that can aid in someones understanding of the nature of particular elements to bond with other elements.

Here are some animations of the Bohr electron shell diagrams for the first 11 elements of the Periodic Table. They provide a great visual.

Atomic Structure Animations 

Modern Atomic Theory: Quantum Mechanical Model

LOUIS de BROGLIE: 1892 - 1987
EWIN SCHRODINGER: 1887 - 1961
WERNER HEISENBERG: 1901 - 1976

In 1924 Broglie purposed that all moving particles, including electrons, exhibit wave like behaviour. Schrodinger explored this idea and in 1926 described an electron as a wave function with the Schrodinger's equation. According to this theory it is impossible to know the exact position and momentum of an electron at the same time. This is known as the Uncertainty Principle and was theorized by Heisenberg. This model uses complex shapes of orbitals which there is likely to be an electron. This model helps explain the spectral phenomena that Bohr's model fails to explain.

Resources:

The Quantum model of the atom is extremely complex and is based on mathematics. I found that the description on the For Dummies web page was effective in explaining the model in a way that I could understand.

Atomic Structure: The Quantum Mechanical Model for Dummies  

Atomic Theory Timeline - Continued Growth

J. J. THOMSON: 1856 - 1940

Thomson drastically changed the billiard ball view of an atom when he discovered the electron in 1897. With the discovery of the electron Thomson suggested that the atom was not an 'indivisible' particle but a jigsaw puzzle of smaller pieces. He used a cathode ray tube and found that the glowing stream within the tube would bend toward a positively charged electric plate. This lead to the theorization that the stream was made up of small particles carrying a negative charge. Thus the electron was discovered. Based on Goldstein's 1886 discovery that atoms had positive charges, Thomson theorized that atoms were like pieces of raisin bread or chocolate chip cookies. They were a structure with clumps of small negatively charged electrons scattered inside a smear of positive charges.

Improvements on previous model:

• Describes the existence of negative and positive charged particles in an atom
• Discovery of the electron

Key problems with the model:

• Does not explain the role of electrons in bonding
• Does not describe neutrons or explain the existence of isotopes

ERNEST RUTHERFORD: 1871 - 1937

Rutherford was a student of Thomson and is known for firing tiny alpha particles at solid objects. His experiment is referred to as the Gold Foil Experiment and is responsible for revolutionizing the view of the atom. In 1911 he suggested that the atom had a dense core of positively charged particles surrounded by a swirling ring of electrons. In his experiment he observed that some of the alpha particles ricocheted off a solid object while others passed through. He theorized that the nucleus was so dense that the alpha particles bounced off of it, while the electrons were very tiny and spread out allowing the alpha particles to pass right through. Rutherford expanded the view of an atom to include electrons, protons, and the nucleus and his model is often referred to as the Planetary Model.

Improvements on previous model:

• Explains why the electron spins around the nucleus
• Purposed that the atom is mostly empty space

Key problems with the model:

• Does not place electrons in definite energy levels around the nucleus
• Doesn't include neutrons in the nucleus

NIELS BOHR: 1885 - 1962

Bohr is a Danish physicist who proposed that electrons could not move continuously in the atom but only in precise steps. He hypothesized that electrons occupy specific energy levels after conducting experiments using atomic spectra. Bohr visualized these energy levels as concentric circles around the nucleus. Bohr also predicted that each energy level could only hold so many electrons. Bohr's theory states that the first electron shell can only hold 2 electrons. For elements that have more than two electrons the third electron will reside in the second electron shell. The second and third electron shells can hold a maximum of 8 electrons each. This model is easily illustrated by drawing electron shell diagrams and explains the role of valence electrons in bonding. This model is the prominent model used in grade 9 science.

Improvements on previous model:

• Explained role of valence electrons in bonding
• Relegates the number of valence electrons to the periods of a periodic table
• Explains ionic and covalent bonding
• Places electrons in definite energy levels

Key problems with the model:

• It doesn't explain the shapes of molecules or other abnormalities

Resources:

I once again used the online VisionLearning virtual text. Here are the two modules:

Atomic Theory 1 

Atomic Theory 2

In my next post I will explain how to draw an electron shell diagram, it's relationship to the atomic mass and atomic number, and examples of my own diagrams. I will also briefly touch on modern Atomic Theory.

Atomic Theory Timeline - In The Beginning

I think that the best format to present what I have discovered about the history of the Atomic Theory and how it directly relates the nature of science is by presenting it in a time line. I also think that this may be a useful assessment that could be used in a science classroom. It would be also neat to have students research one particular scientist and present their findings to the class. You could create a living timeline with your students.

DEMOCRITUS: 460 BCE - 370 BCE

Our current understanding of the atom has been in the making for thousands of years and began with the Greek philosophers/scientists. Prior to Democritus, Empedocles had described a theory that matter was composed of four core elements, water, fire, air, and earth. Empedocles theory was problematic as it did not describe why when you break a rock in half the pieces never resembled any of the core elements. Democritus developed a new theory to overcome the problems of his predecessor. He suggested that there were infinitesimally small pieces of matter which he called atomos, meaning 'indivisible.' Democritus suggested that atomos were eternal and could not be destroyed, and also that these atomos were unique to the material that they made up. This theory attempted to explain the whole physical world.

Improvements on previous model:

• Talks about the atom as the smallest particle of matter
• Defines the atom as an indivisible particle
• Attempts to explain the existence of elements

Key problems with the model:

• The view is not scientific but rather a conceptual definition of the atom
• Does not describe subatomic particles 

 JOHN DALTON: 1766 - 1844

Dalton was a British teacher and scientist who is credited with developing the first modern atomic theory in 1803. He used the foundations laid by other chemists Priestley and Lavoisier along with his own discoveries from studying weather to determine that matter must be composed of tiny particles. Dalton's theory is often referred to as the solid sphere model as Dalton pictured atoms as tiny billiard-ball like particles in various states of motion. There are four key concepts in Dalton's theory:

1. All matter is composed of indivisible particles called atoms
2. All atoms of a give element are identical; atoms of different elements have different properties
3. Chemical reactions involve the combination of atoms, not the destruction of atoms
4. When elements react to form compounds they react in defined, whole-number rations or in other words reactions are not random events. 

Improvements on previous model:

• Explains many chemical properties such as how atoms combine to form molecules
• Explains chemical change

Key problems with the model:

• Does not include the existence of the nucleus
• Does not explain the existence of ions or isotopes
• Does not describe subatomic particles

This concludes the first part of my Atomic Theory time line. It is obvious that scientists built upon the work of others to produce a more accurate explanation of the world. This is a great example of how the nature of science works and how incorrect theories can contribute to important scientific discoveries. 

Resources:

The vast majority of my information was found in the virtual textbook VisionLearning. This online source contains numerous modules with online quizzes and interactive links to aid in learning. The online source is presented like a interactive textbook and includes modules for numerous science topics form biology to chemistry and it is free.

In the Beginning  

Curriculum Connection

In order to focus my learning I feel that it is important to connect what I am learning to what I would be teaching. Therefore I am including the SCO's for Science 9 that are connected to Atomic Theory and the Periodic Table. The following outcomes have been taken directly from the Atlantic Canada Science 9 curriculum documents and are being included for informational purposes only.

Atomic Theory

• Use models in describing the structure and components of atoms and molecules, and explain the appropriate operational definition (307-14, 208-7)

Periodic Table

• Identify examples of common elements, and compare their characteristics and atomic structure (307-15)
• Use the periodic table as a classification system and compile data about its structure (210-1, 210-2)
• Identify the elements and number of atoms, given a chemical formula (307-16)
• Provide examples of scientific knowledge that have resulted in the development of technologies (111-1) 
• Provide examples of technologies that have enhanced, promoted, or made possible scientific research (111-4) 
• Explain and provide examples of how society’s needs for chemistry incorporate science, technology, and environment (112-3, 112-8)

Although I took science during my own personal high school experience it amazes me at how little I recall from introductory chemistry. I think that the foundation of chemistry lies in having a concrete understanding of the Periodic Table and how matter is formed which grade 9 science is focused on. After briefly searching Atomic Theory in Google it amazed me at how little I remember. There were so many individuals involved in the discovery of the atom and the history of this discovery is facinating. I think that understanding how scientific knowledge evolves is important for our students and the study of the Atomic Theory helps present just that. Having students study the history of a theory such as Atomic Theory helps present the true nature of science and how science changes and evolves over time. In my next post I will be taking a closer look at the timeline of the Atomic Theory including some of the key players involved in developing the theory. 

Beginning The Rediscovering Process

HELLO!

My name is Jenn Roop and I am currently completing my BEd. I plan on being a secondary science teacher and realize that I need to brush up on chemistry if I intend to provide the best teaching possible. I have decided to start off my chemistry rediscovery from the beginning, with the basics. In the Atlantic Canadian Science 9 curriculum, Atomic Theory and introducing the basics of the Periodic Table of Elements is a key topic or unit. As it is very likely I will be responsible for tackling Science 9 and 10 during my career I have chosen a topic from the grade 9 curriculum to focus my self-directed learning on.

I also wanted to mention that I am new to the blogging world and am excited to discover and learn about the blogging process and perhaps how it could be utilized in a secondary science classroom. I am excited to begin the process and hopefully create a place to share the resources I find. Below you will find my contract for my self-directed learning process. I hope you enjoy following me during my rediscovery of basic chemistry.


Objectives – What are you going to learn?

• The history of Atomic Theory including who, what, where, and why
• How to draw and interpret electron cloud diagrams
• The connection between Atomic Theory and the Periodic Table of Elements
• General trends found throughout the Periodic Table of Elements
• Develop a confidence in my understanding of the Periodic Table of Elements including where to find particular facts within the table

Resources/Strategies – How are you going to learn it?

• Internet 
• Interactive Periodic Table of Elements
• Textbooks
• Peers/Colleagues
• Video Demonstrations

Target date for Completion

• February 7th, 2012

Evidence – How are you going to know when you’ve learned it?

• When I feel comfortable explaining the Atomic Theory to someone who is familiar with chemistry and I can successfully draw an electron cloud diagram without any assistance
• When I feel confident that I can use a find information and use a Periodic Table of Elements on my own and explain the trends clearly and concisely. 
• When I fell confident with my understanding of terminology and basic understanding. 
• When I can confidently answer this question with a yes; Could I teach this topic in a grade 9 science class?

Verification – How are you going to prove you learned?

• Create a Blog which follows my rediscovery and learning journey
• Have a conversation with a chemistry teacher or expert in the field. 

Well I guess that this concludes my first entry. I am now on my way to sharing my learning journey with you and can officially call myself a 'blogger'. 

Jenn