For the average person, a periodic table is something that brings back memories of high school science classes, but it can be a treasure trove of information. If you’ve forgotten your lessons, don’t worry — we’re here to make things a little easier for you. To help you navigate the data available, we’ve pulled together some everyday uses for a number of different element groups, starting with the Alkali Metals.
What are alkali metals and where might you encounter them in your everyday life?
Properties of Alkali Metals
The periodic table is divided into groups based on the number of electrons in each element. Group 1 is known as the alkali metals. What are the alkali metals? They include:
All of these metals have a single electron in their outer orbit and thus display very similar physical properties. They’re all soft metals that can be easily cut. All of the alkali metals, with the exception of cesium, are also white in their pure state.
Chemical and Physical Traits
Other than their physical similarities, what traits indicate the presence of an alkali metal?
First, all of these chemicals are usually not found in their pure state in nature because they are very reactive. The violence of their reactions varies depending on the individual metal, but they will react when they come into contact with water. Some, like sodium and cesium, react so violently that they can even explode! That’s why these chemicals are normally found as salts.
They also tarnish very quickly when exposed to air. If you’re not sure which alkali metal you’ve got on hand, you can light it on fire to determine which one you have — they all burn different colors. A quick flame test will show:
- Lithium burns red
- Sodium burns orange
- Potassium burns lilac (pink)
- Rubidium burns red-violet
- Cesium burns blue or blue-violet
In their pure state, these metals are almost always stored in oil or another non-reactive substance.
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Where might you encounter alkali metals in your everyday life? Here are some examples:
- Lithium: Found in lubricants as well as some glass and lead alloys. You can go to your local auto parts store and find tubes of white lithium grease, which is used for delicate moving parts. It’s also used in psychiatric treatments as a mood stabilizer for individuals with bipolar disorder and schizophrenia.
- Sodium: The most ubiquitous use of sodium is in the form of sodium chloride, or table salt. You might also find it under your kitchen sink, or wherever you keep your cleaning supplies, in the form of sodium borate, which is also known as borax. There isn’t much use for pure sodium because of its volatility, but there are many sodium-based compounds that are used every day all over the world.
- Potassium: Look again to your kitchen table for this one. Potassium is found in bananas and other natural foods. In its chemical form, it’s so volatile that it can’t be stored in anything other than kerosene. In the past, it has also been used, in the form of potash or potassium carbonate, to create soap and glass, and, in the form of potassium nitrate, to make gunpowder.
These are the only three alkali metals that you might encounter in your home. What uses have been found for the remaining three alkali metals?
- Rubidium: While this was one of the first metals discovered using a spectroscope, which is able to photograph a chemical’s “energy fingerprint,” there haven’t been many, if any, uses discovered for it. It’s also not a terribly abundant metal, even though it’s more common than either cesium or francium.
- Cesium: You probably won’t find this metal in your home, but it does have many more applications than rubidium or francium — namely in things like photoelectric cells, video equipment, radio tubes and military-grade infrared lamps.
- Francium: There is too little francium on the planet for it to have any real applications — they’ve theorized that if scientists were able to collect all the francium in the Earth’s crust, it wouldn’t amount to more than 25 grams of the stuff.
Where have you spotted alkali metals in your everyday life? If you’ve got any questions about alkali metals or about any of our previous or even upcoming posts, let us know! We’d love to hear from you!
Read about more chemistry-related discoveries here!