We encounter a variety of different elements every single day, from the fluoride in your toothpaste to the sodium and chlorine in your table salt, but some of them are more common than others. Today, we’re going to take a closer look at some elements that you might not encounter — or want to encounter — during your daily activities: the semimetals. What are metalloids and where might you use them during your everyday activities?
Metalloids, also known as semimetals, fit between the metals and nonmetals on the periodic table, but what are metalloids, really? They are tricky to define because they have what is known as intermediate properties, meaning they can present properties that could belong to either the metals or nonmetals group. There’s no definitive answer as to which group these elements belong. For most scientists, it’s a judgment call.
Yes, you read that right. Even scientists have trouble answering the question ‘what are metalloids?’
The elements ‘officially’ included in the semimetals group are:
Silicon is the second most abundant element found in the Earth’s crust. The only element more abundant is oxygen.
Another thing that is strange about the semimetals on the periodic table is that they don’t appear on the periodic table in a straight vertical or horizontal line – their group line is diagonal.
Chemical and Physical Traits
Elements belonging to the semimetals group can be strange. They look like brittle metals, but their chemical behavior is distinctly non-metallic. They can, and generally do, form alloys with the metals around them, making them stronger and giving them metallic properties.
Whether or not these elements present metallic properties depends on the substances with which they’re interacting. Boron, for example, will act like a nonmetal when interacting with the volatile element sodium but will behave like a metal element when interacting with fluorine.
One of the most coveted properties of metalloids is the fact that under certain conditions, they can act as conductors. This trait, of only conducting electricity under certain circumstances, is known as semiconductivity.
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Where might you find these elements during your daily activities? Most of them are more common than you might think. What are some of the common uses of metalloids in our daily life?
This is easily one of the most useful elements on the planet. If you’re reading this article on an electronic device, then you’re utilizing silicon. It’s used in computer chips because of its semiconductor status and is mixed with other elements, including boron, gallium and phosphorus, to increase its conductive ability.
Silicon is also present in rubber, in the form of silicones which polymers formed between silicon and oxygen. You probably have some of this in your home. It’s used as a waterproof sealant in bathrooms, on roofs and around water pipes.
If you drove to work or school today, you used silicon. Aluminum-silicon alloys are used to make engine parts, including the block and cylinder head that makes up the core of your car’s engine. Silicon may have also been used to make the mirrors and windows in your car as well as your home, and a dioxide of silicon may also be scattered across your front yard as sand.
You run into silicon everywhere – even if you don’t realize it.
If you’ve ever seen a fireworks display that featured green explosions, you’ve seen boron in action. This element is frequently used to change the color of fireworks because it burns green. This might be one of the most explosive uses of metalloids in our daily life, at least until you make it down to tellurium.
You probably have some boron in your kitchen or garage, in the form of boric acid or borax. It’s a fantastic cleaning agent and can even be found in things like eye drops and in foods as a preservative. It’s non-toxic in small amounts and can an act as a semi-natural pest control method.
If you’ve got any glass cookware that sports the brand name Pyrex, you’ve got more boron in your home. Pyrex is comprised of borosilicate glass, which combines both boron and silicon to make long-lasting cookware that is heat resistant and will last long enough for you to pass down to your grandchildren. You need to make sure that you get Pyrex dishes from France though. The company no longer makes or sells borosilicate glass in the United States, opting instead for a soda-lime glass that isn’t as resistant to thermal shock.
You won’t generally find germanium in your kitchen unless you’ve got a smart fridge. Its primary use is in the semiconductor industry. Like silicon, germanium is mixed with various other elements to improve its conductive properties, so you can most often find it in electronic devices.
This element can also be used in fluorescent lamps and infrared detectors. Some studies suggest that germanium can be used to kill bacteria, and it may have future applications in chemotherapy treatments.
This is one element that you don’t want to run into! Arsenic is toxic and has been used historically for assassinations, but that doesn’t mean that it doesn’t have any uses. It’s not just toxic to humans. It’s toxic to other creatures too, which makes it ideal for wood preservation and use in insecticides. When mixed with gallium, it becomes a semiconductor and is often used in LEDs.
If you enjoy hunting or target shooting, you may be using more arsenic than you realize. The lead alloys used to make bullets often contain it.
Oddly enough, a small amount of arsenic is necessary for the human body to grow and thrive. Studies have shown that arsenic has a role in the metabolism of some amino acids and may play a role in gene silencing – the body’s natural response to prevent the expression of a particular gene. Thankfully, the small amount that we encounter in our natural food supply is more than enough to supply our body with this micronutrient, so don’t go looking for it in your local pharmacy.
The ancient Egyptians used antimony as a cosmetic, centuries before scientists officially discovered it in 1707. In its pure form, it acts as a semiconductor in things like diodes. Once alloyed with other metals, it is used in batteries, cable sheathing and other similar applications.
You may also find it in your art class – the Egyptians had the right idea there. Antimony is an ingredient in paints and ceramic enamels and can also color glass and pottery.
Tellurium is an element that is primarily used as an additive to create alloys. It makes copper and stainless steel easier to machine and shape and increases lead’s resistant to acidic corrosion. It is added to cast iron and ceramics to prevent thermal shock.
If you have a fondness for explosives, you might be familiar with tellurium – it’s one of the primary ingredients in blasting caps.
This is one of the rarest elements in the semimetal family, and all the commercially used polonium in the world comes from Russia. It isn’t a semimetal that you’re encounter in your daily life. That’s a good thing, as it’s highly radioactive and toxic to humans.
Polonium has powered several lunar rovers, and its use on Earth is limited to research purposes. Marie Curie first discovered it. The element gets its name from her home country of Poland.
Some of these elements are definitely more common than others, but they all have their uses. The next time you pick up your cell phone or boot up your computer, remember to thank Jons Jacob Berzelius who discovered silicon in 1824. The modern computing age wouldn’t be possible without him!
Read about more chemistry-related discoveries here!