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An image showing the symbol, atomic number and relative atomic mass of sodium. Sodium’s symbol is Na, its atomic number is 11 and its relative atomic mass is approximately 22.99.  Image © istockphoto.com/3dalia

An image showing the symbol, atomic number and relative atomic mass of sodium. Sodium’s symbol is Na, its atomic number is 11 and its relative atomic mass is approximately 22.99.  Image © istockphoto.com/3dalia

STEM in Context

Na Na Na Na (Hey Hey Hey) Sodium!

Kelly Resmer and Let's Talk Science

Summary

Sodium is a useful chemical element. You consume it as table salt regularly. Learn about salt mining, sodium uses, and what problems too much sodium can cause.

Name: Sodium
Symbol: Na
Atomic Number: 11
Relative Atomic Mass: 22.99
Category: Alkali metal
Appearance: Silver coloured metal

Sodium is a very important and useful chemical element. It is also one that needs to be treated with care in its elemental form. An element is in its elemental form when it is not combined with other elements as part of a compound.The elemental form of sodium is very reactive. It can even explode and cause fires when it’s in water! Because of its reactivity, sodium is never found in its elemental form in nature. 

When sodium is placed into water, it undergoes a chemical reaction which produces sodium hydroxide and hydrogen gas (0.46 min.).

 

Did you know?

Sodium is in the first group (column) and third period (row) of the periodic table

Let’s learn where sodium comes from, how it is used, and why it can cause problems for cars and for humans.

Did you know?

Sodium is one of the 10 most abundant elements on Earth. It makes up 2.6% of the Earth’s crust. 

Where does salt come from? 

Salt, in the form of NaCl (sodium chloride), is mined across Canada. In the Atlantic provinces, it comes from ancient inland seas that have since dried up. In its mineral form, sodium chloride is called halite.

Where is the world’s largest salt mine?

The world’s largest underground salt mine is in Goderich, Ontario. The salt mined in Goderich is from an ancient sea bed that existed in the area during the Silurian Period, between 443 million and 416 million years ago. When that sea dried up, the salt was left behind in a huge layer of sediment. Over time, the sediment was covered by layers of rock and soil. The layer of salt in Goderich, which is over 300 m below the bottom of Lake Huron, is more than 40 m thick.

This video shows you how salt is mined at the Sifto salt mine in Goderich, Ontario (2:23 min.).

 

 

Here, the giant deposits found deep underground are drilled and blasted to break off smaller pieces. Salt mined in this way is not pure. In order to be purified, the salt is dissolved. Then, the water is evaporated. This allows the salt to recrystallize, and any impurities to be washed away. 

What are some of the uses of salt?

There are many uses for sodium-containing salt. For example, it is used as a de-icer for roads in the winter in some parts of Canada. Sodium and chloride ions move around with the water molecules, making it harder for them to form ice crystals. As a result, ice forms at a much lower temperature than it would normally. Sodium chloride can actually lower the freezing temperature of water from 0°C to -21°C. However, salt is very corrosive.  This means that it damages other materials, especially metals. This is why so many cars begin to rust after years of salt exposure. The use of road salt also has a variety of environmental impacts

The series Reactions looks at the science behind rock salt and how it melts ice (3:12 min.).

 

 

 

Did you know?

Sodium is found in many common household products, including table salt (sodium chloride), baking soda (sodium bicarbonate), and a laundry detergent booster called borax (disodium tetraborate). 

How does sodium affect the human body? 

All of the cells in your body need sodium.  Sodium allows your muscles to contract and your nerve cells to communicate. However, if you get too much sodium, it can be very bad for your health. Taking in too much salt in your diet can raise the amount of sodium in your blood. The extra sodium in your blood causes your kidneys to work extra hard to pull out water to produce urine. This can cause excess fluid and strain on the blood vessels around the kidney. Over the long term, this can lead to kidney disease or hypertension (high blood pressure). Hypertension can lead to heart attacks and strokes.

Adults and children over the age of 13 should only take in between 1 500 and 2 300 mg of sodium a day. This is less than one teaspoon of salt. However, on average, Canadian males aged 14 to 18 tend to take double the recommended amount of sodium: 3420 mg a day! (5) To avoid consuming too much sodium, avoid eating too much bread and processed meat, both of which are major sources of sodium for Canadians.

To sum up...

Sodium is a very important component of sodium chloride, the salt we use to flavour our foods and salt our roads. But salt can be corrosive to cars. It can also cause some pretty serious health consequences if you eat too much of it. Remember, sometimes there can be too much of a good thing!

Starting Points

Connecting and Relating
  • Does anyone in your family have to limit the amount of salt in their diet? If so, why?
  • Have you or anyone in your family experienced salt damage to clothing or footwear? How did you get rid of the salt stains?
  • It is recommended that adults and children over the age of 13 consume only 1 500 to 2 300 mg of sodium a day. Chart your daily salt consumption. Is it more or less than the recommended amount?
Connecting and Relating
  • Does anyone in your family have to limit the amount of salt in their diet? If so, why?
  • Have you or anyone in your family experienced salt damage to clothing or footwear? How did you get rid of the salt stains?
  • It is recommended that adults and children over the age of 13 consume only 1 500 to 2 300 mg of sodium a day. Chart your daily salt consumption. Is it more or less than the recommended amount?
Relating Science and Technology to Society and the Environment
  • Explain how using salt to de-ice roads is an example of the interaction of science, technology, society and the environment.
  • Should special taxes be placed on foods high in salt to help fund the healthcare system?  Why or why not?
  • Sleet and hail have been falling all night and the windshield of the family car has a thick coating of ice. Should you use salt to remove the ice from the windshield?  Why/why not?
  • Imagine you are the mayor of a town and you must decide to use either salt or sand on the roads in your town this winter.  What arguments could be made for the use of salt?  What arguments could be made for the use of sand?  Which one would you choose and why?
Relating Science and Technology to Society and the Environment
  • Explain how using salt to de-ice roads is an example of the interaction of science, technology, society and the environment.
  • Should special taxes be placed on foods high in salt to help fund the healthcare system?  Why or why not?
  • Sleet and hail have been falling all night and the windshield of the family car has a thick coating of ice. Should you use salt to remove the ice from the windshield?  Why/why not?
  • Imagine you are the mayor of a town and you must decide to use either salt or sand on the roads in your town this winter.  What arguments could be made for the use of salt?  What arguments could be made for the use of sand?  Which one would you choose and why?
Exploring Concepts
  • Describe three physical properties of sodium.
  • What is the most common chemical compound made with sodium?
  • How do humans get sodium chloride into their bodies? Why do we need it?
  • Describe another way people use salt besides as an ingredient in food and on roads.
Exploring Concepts
  • Describe three physical properties of sodium.
  • What is the most common chemical compound made with sodium?
  • How do humans get sodium chloride into their bodies? Why do we need it?
  • Describe another way people use salt besides as an ingredient in food and on roads.
Media Literacy
  • Imagine you are a dietician who is very concerned about the rise of hypertension in your area. What kind of awareness campaign would you create? Design a poster, pamphlet or short video to bring awareness to this issue.
  • Design a poster or other media product to convince people to control the amount of salt in their diets.
Media Literacy
  • Imagine you are a dietician who is very concerned about the rise of hypertension in your area. What kind of awareness campaign would you create? Design a poster, pamphlet or short video to bring awareness to this issue.
  • Design a poster or other media product to convince people to control the amount of salt in their diets.
Teaching Suggestions
  • This article can be used to support teaching and learning in Chemistry, Health & Human Body, and Earth & Environment related to chemical elements, compounds and mining. Concepts introduced include chemical elements, compounds, dissolving, evaporation, recrystallizing, muscles, nerve cells, blood, kidneys and hypertension.
  • If using this article to support Health & Human Body learning, the teacher could have students bring in food labels from a variety of common foods and snack foods before reading the article. After reading the article, students could look for evidence of sodium in each of the food products and compare the relative amounts in each product. 
  • After reading the article, students could create questions for further discussion or exploration using a Question Creation Chart (QC2) learning strategy. Download ready-to-use Question Creation Chart reproducibles for this article in [Google doc] or [PDF] formats. 
  • To support Chemistry teaching and learning, students could conduct further research and then create an illustrated graphic organizer or infographic that demonstrates the various uses/applications of salt in society and daily life. 
Teaching Suggestions
  • This article can be used to support teaching and learning in Chemistry, Health & Human Body, and Earth & Environment related to chemical elements, compounds and mining. Concepts introduced include chemical elements, compounds, dissolving, evaporation, recrystallizing, muscles, nerve cells, blood, kidneys and hypertension.
  • If using this article to support Health & Human Body learning, the teacher could have students bring in food labels from a variety of common foods and snack foods before reading the article. After reading the article, students could look for evidence of sodium in each of the food products and compare the relative amounts in each product. 
  • After reading the article, students could create questions for further discussion or exploration using a Question Creation Chart (QC2) learning strategy. Download ready-to-use Question Creation Chart reproducibles for this article in [Google doc] or [PDF] formats. 
  • To support Chemistry teaching and learning, students could conduct further research and then create an illustrated graphic organizer or infographic that demonstrates the various uses/applications of salt in society and daily life. 

Learn more

Sodium: the essentials (2015)

A brief article on WebElements about Sodium, giving information about the properties, uses, and reactions of this element.

The Element Sodium

Jefferson Lab gives further information on Sodium, such as its estimated abundance on Earth.

Periodic Graphics: Deicers And Antifreeze (2015)

Infographic from the American Chemical Society on different types of deicers, including sodium chloride, and their uses.

Salt in Canada (2014)

Brief overview of salt mining in Canada from Compass Minerals. 

Sodium in Canada (2012)

Information from Health Canada about sodium, including the benefits of consuming sodium, and the dangers of consuming too much.

Salt’s effects on your body (2008)

Blood Pressure UK website with information on salt consumption and associated health risks.

A pinch of sodium (2011)

Short article from Margit S. Müller discussing the importance of sodium, including its industrial applications and its biological role.

References

Government of Canada. (2018). Sodium intake of Canadians in 2017

Hewitt, D. F. (1962). Salt in Ontario (industrial mineral report No. 6). Ontario Department of Mines.

New Hampshire Department of Environmental Services. (n.d.). Water quality impacts - Environmental, health and economic impacts of road salt.

Pohl H.R., Wheeler J.S., Murray H.E. (2013). Sodium and potassium in health and disease. Metal Ions in Life Sciences, 13. DOI: 10.1007/978-94-007-7500-8_2

Summers, J., & Valleau, R. (2017). Road salt makes winter driving safer, but what does it do to the environment?. The Conversation.