Whether a precious metal or not, all metals carry unique attributes that can differentiate them from metalloids and nonmetals. Every metal carry a series of physical and chemical properties that can be applied equivalently.
However, some metals can be particular to a single characteristic that makes them special. Basic Properties of Metals are color, shine, conductivity and reactivity.
Metals can be easily separated from nonmetals with their basic properties, but not so much from metalloids. You see, metalloids have similar characteristics as metals, but theirs are weaker and poor in value.
For example: Gold is a shiny metal, silicon is a metalloid that can be shiny if it’s glass or not when it is soil. Nonmetals on the other hand, are mostly gas like oxygen, some are solid like sulfur and only one is liquid: Bromine.
So as you can tell, shine is a good property to tell a metal from a nonmetal, but may not be the best way to differentiate it from a metalloid.
A better way of recognizing metals from metalloids are malleability and conductivity. Metals are flexible and ductile in nature, meaning you can hammer them and press them, they are hard but with enough heat and pressure metals turn to jelly.
Unlike metalloids that are brittle. Metals also are great conductors of heat and electricity such as silver.
Properties of metals can be categorized as physical and chemical.
- Natural state
The only thing that stands between a physical property and a chemical property of a metal is the attribute of permanent change in a molecular level. You see, when a metal undergoes physical change, it does not affect its nature.
Unlike chemical variation where the metal is no longer the same in its core.
Physical Properties of Metals:
All metals are solid at room temperature (25 degrees Celsius), except for mercury, which is liquid. They are almost always found in rocks as alloys, meaning when you go mining in a mountain, you may find iron, cobalt and nickel mixed together, or if you are lucky a gold or platinum ore.
Except for native metals (Gold group and Platinum group), the remaining ones often go through chemical reactions such as corrosion and oxidation, thus cannot be found in large amounts and in need of purifying.
Upon finding a metal ore, humans have been able to separate metals from nonmetals with a method called smelting. Smelting is the process of applying heat to the metal ore until the rock melts away and the metal remains.
It is also beneficial in separating alloyed metals since each one has different melting points. Humans have used this method since 6500 BC.
Metals are not much diverse in color, except for copper that appear to be red, the remaining are shades of white (silver), grey (lead) and yellow (gold). Metal colors comes from the absorption and diffusion of light rays.
The color also tells us which metal is present in a substance. This method is known as flame test and is used on all elements. The process involves burning the substance with a hot non-luminous flame and observing the change in color of the flame.
Different metals give different flame colors, such as:
- Iron gives golden or orange colored flame
- Mercury gives red
- Tungsten gives green
- Cobalt gives silver-white
- Copper gives green or blue-green, and
- Zinc is colorless
Even though the flame test provides information only on nature of the element, the amount present can be detected through another method called flame photometry.
Luster, also known as shine or reflectiveness of a metal, is determined upon in what length does the metal reflect light wavelengths. The longer the wavelength, the shinier the metal.
The long or short wavelengths of reflected light depends upon how many electrons does the metal atoms have circling farthest from the nucleus. Light rays bounce off of these farther electrons, since the closer ones are covered in cloud.
Humans have always admired shiny objects and have used them in jewelry and art. That is why most of our necklaces and rings are made from lustrous metals like gold and nonmetals like diamonds.
The most reflective metal is silver, followed by palladium, osmium, iridium, gold, platinum and rhodium.
When metals are hammered and pressed without breaking, it is known as their malleability, and when rolled into thin wires, their ductility.
Unlike nonmetals and metalloids that are brittle and cannot be hammered, most metals are able to be shaped and stretched out, although some can break under immense pressure like titanium or tungsten.
In a molecular level, malleability is defined as the feature of metal atoms rolling over each other without breaking their bonds. Metals increase their lamination when heated.
A good example of this would be copper and gold, except for lead and tin since they are more flexible while colder and breaks if heated.
Gold is the most malleable and ductile metal, followed by silver, lead, copper and aluminum. It can be hammered up to 0.002 millimeters in thinness and almost as light as 50 grams of it can be stretched to 5 meters long. No wonder jewelers love to work with it so much.
Density is the amount of mass per unit volume. In simple terms, the more number of atoms a metal has in a centimeter cube (or meter cube), the more dense it is. Just like luster, number of delocalized and farther electrons of a metal dictates its density as well.
Density is usually measured in grams per centimeter cube, and should not be confused with atomic weight, which is the amount of gravitational force applied on nucleus of an atom.
In general, metals are denser than nonmetals. Some metals are surprisingly denser than other ones such as mercury and lead in a way that even though solid and heavy, an anvil made out of lead will float in a pool of mercury because the latter is 2 grams denser.
That being said, the densest metal is osmium with 22.6 grams/centimeter cube followed by iridium which is only 0.02 grams lighter, the rest are platinum, neptunium, plutonium, tungsten, gold and uranium.
This property of metal comes in two types, temperature and electricity. All metals naturally transfer them to a level, although some are better than others such as silver, copper and gold.
The free-to-move (valence) electrons inside metal atoms are also responsible for the flow of heat energy and electricity.
Unlike properties of luster and density, in conductivity it’s better if there are less valence electrons, because the energy will remain and transfer stronger.
In other words, heat and electrical energy will jump from one electron to another in 100% capacity, where the same energy will be divided into half if there are two electrons carrying it, and in quarter if four.
Thus, the most conductive metals are also the ones having single free-flowing electrons in their atoms’ outermost shell.
The opposite of electrical conduction is called resistivity, and is measured in ohms. While metals are good conductors, metalloids and nonmetals are great insulators.
Chemical Properties of Metals:
Tarnish and corrosion are the two most basic chemical changes a metal undergoes if exposed to air or water, the difference is that tarnish only affects the external layer of a metal (patina), while corrosion does it all the way (rust).
Usually when the metal loses its shine and turns grey or black, it is because of tarnish, and once the outer layer stains, it protects the inner ones from reacting.
Tarnish is often a metal oxide and sometimes metal sulfide. The existence of patina is crucial in copper roofing and bronze or brass statues.
Most jewelry made out of gold, silver or platinum will experience this in time, but don’t worry it is not like rust and can be removed with steel wool, sand paper or baking soda.
Also known as rust and oxidation, corrosion is a chemical reaction that occur to the most reactive metals such as iron.
When exposed to air or water for longer times, high reactive metals enter a reaction in order to get better stabilized, and forms compounds such as oxides, hydroxides and sulfides. Corrosion weakens a metal’s strength and appearance.
The noble metals, which most jewelry are made out of, do not experience corrosion because of their non-reactivity. However, even if they do, there are ways to remove it to some extent. Putting the corroded metal in acidic solutions, baking soda or even a potato, can help you.
These are the metals and compounds that are most resistant to corrosion: Copper, aluminum, stainless steel and precious metals like gold, silver and platinum.
Some metals are poisonous to humans, mostly when they form particular compounds. If they find their way inside the body, it can lead to nausea, diarrhea, vomiting, shortness of breath and weakness.
Usually toxic metals are from heavy metal group, but some light metals such as beryllium and lithium can poison you too. The most toxic metals are cadmium, manganese, lead, mercury and radioactive metals like uranium.
We are exposed to metals in our everyday lives. The bad thing about metal toxicity is that it cannot be cured like organic poisons, if you are exposed you need to get rid of the metal in your body immediately otherwise it may lead to cancer and even death.
There is a method of removing poisonous metals called chelation therapy. It involves using the chelating agents, which have electron donating groups, resulting in stabilizing the metal. However, chelation therapy is not safe and can have side effects as well.
Among the precious metals, only silver has poisoning properties called argyria. If you are exposed to silver compounds or dust, argyria will find you and turn your skin blueish-grey.
That is a good way to look like Kratos from God of War if it is Halloween season (joking, be careful of silver toxicity).
An element is made of atoms, and the atom consists of protons and neutrons in its nucleus, and electrons in shells. Radioactivity occurs when the nucleus of the element is unstable and in a state of emitting energy in forms of alpha/beta particles or gamma rays.
There are a number of natural radioactive elements including some metals such as uranium, radium, plutonium, thorium, cesium and polonium, of which the latter is considered the most radioactive.
It is worth mentioning that humans have also created some radioactive elements like technetium, curium and californium.
Today, these elements (natural and synthetic) are being used in many ways, including smoke detectors, coal burning plants, nuclear power plants and of course atomic bomb detonations.
The famous atom bombs that were used on japan during world war 2 had uranium-235, a naturally occurring radioactive metal, in its core.
Exposure to small amounts of radiation once in a while is not dangerous, these include microwave, radio waves, ultraviolet lights and x-rays.
However, too much of them can be harmful. In huge amounts, radiation will result in burns, genetic alterations, infertility, abortion in women, cancer and death. If you feel curious and have the heart, then watch the miniseries Chernobyl.
Elements have positive, negative or neutral charges. The neutral elements (noble gases) do not react with any element, but the rest of them can experience reactions with each other under special circumstances.
Whenever a reaction occurs between elements, the ones (mostly nonmetals) with negative charge are in need of electrons, so they take them from the ones (mostly metals) that have extra.
Electropositivity is a common attribute of metals. They carry extra electron(s) in their outermost shell, and upon finding a suitable partner in need, they donate them.
A good example can be sodium and chlorine. Sodium (an alkali metal) is charged +1, and chlorine (a halogen) -1. When they react, sodium donates that one extra electron to chlorine and together they form table salt.
Some nonmetals experience electropositivity as well, such as hydrogen. Two atoms of hydrogen (a gas) with +1 charge reacts with one atom of oxygen charged -2, and with the help of lightning energy, they form water. The opposite of electropositivity is electronegativity.
Metals are fascinating objects. If we pay attention, we can observe that metals surround us, from the home we live in, the car we drive and the mobile we use, each of them consists of various metals.
It is believed that our planet did not contain as many metals as it has now, and some quite important metals came down from space such as iron.
I sincerely hope that you have enjoyed yet another informative list about Properties of Metals I prepared for you. If you feel some parts of the information is incorrect or misleading, drop a comment. I would appreciate your opinion and honesty.
Best of Luck!