Take a quick look around you and you'll see that many things in your life are made of metal or have metal parts. Your watch has metal gears and your frying pan has a metal bottom. Even your jewelry made of gold or silver is a type of metallic solid!

So, what exactly are metallic solids? Simply put, they are materials that are made up of metal atoms arranged in a specific way. These solids have unique properties such as being good conductors of electricity and having a shiny appearance. But not all metallic solids are the same. There are different types with varying properties. Some are malleable, meaning they can be hammered into different shapes, while others are brittle and can break easily. One type of metallic material that you may have heard of is a metallic alloy. This is a combination of two or more metals, which changes the properties of the material. For example, stainless steel is a metallic alloy made of iron, carbon, and other metals. It is strong, resistant to corrosion, and commonly used in kitchen appliances and construction. In conclusion, metallic solids are all around us, and understanding their properties and uses can help us appreciate the many ways in which they make our lives easier and more convenient.

What is a Metallic Solid?

Metallic solids are materials that consist of metal atoms exclusively, giving them a unique set of properties. They are held together by a special type of bond called metallic bonding. This occurs when a lattice of positively charged metal ions is surrounded by a sea of delocalized electrons.

To put it simply, metallic bonding is what makes metallic solids strong, malleable, and good conductors of heat and electricity. Metals like copper, iron, and aluminum are examples of metallic solids that we use in our daily lives. If you want to learn more about metallic bonding and its role in the properties of metallic solids, check out the article "Metallic Bonding Explained" for a more in-depth explanation.

Structure of Metallic Solids

When it comes to solids, there are two main categories: crystalline and amorphous solids. Crystalline solids have a highly organized and repeating atomic structure, while amorphous solids lack any organized structure.

Metallic solids fall under the category of crystalline solids, meaning that their atoms are arranged in a highly ordered and repeating pattern. In metallic solids, the crystal lattice is made up of positively charged metal ions surrounded by a "sea" of free-flowing electrons. This unique structure is what gives metallic solids their characteristic properties, such as their ability to conduct electricity and their malleability.

To better understand this structure, take a look at a drawing of the lattice structure of a metal like sodium (Na). You'll notice that the sodium atoms are surrounded by a cloud of free-flowing electrons, which are attracted to the positively charged sodium ions. It is this attractive force that keeps the sodium atoms closely packed together in a solid. Overall, understanding the structure of metallic solids can help us appreciate their unique properties and their many uses in our daily lives.

Metallic Solid Examples

Some common examples of metallic solids include aluminum (Al) metal and Potassium (Na) metal.

Aluminum (Al) is a metal found in group 13 (also called IIIA in some periodic tables). It has a high melting point of 660.32 °C and has a face-centered cubic crystal lattice structure.

Potassium (K) is a group 1 metal and has a melting point of 63.38 °C. Potassium has a body-centered cubic crystal lattice structure.

Not sure what a face-centered or body-centered cubic lattice structure means? You might want to check out "Solids"!

Properties of Metallic Solids

Before diving into the properties of metallic solids, let's review the periodic trend of metals! Remember that, except for mercury (Hg),  metals are solids at room temperature.

Group I metals are known as the alkali metals (Li, Na, K, Rb, Cs, Fr)Group II metals are called the alkaline earth metals (Be, Mg, Ca, Sr, Ba, Ra)Groups 3-12 contain many transition metals such as Fe, Cu, Ag, and Au.Group 13-16 also have some metals called post-transition metals or poor metals (Al, Ga, In, Tl, Pb, Sn, Bi, and Po).

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Metallic Character of Metallic Solids

The metallic character of an element is a measure of how closely its properties resemble those of a metal. Elements that exhibit the characteristics of metals, such as good conductivity, ductility, and malleability, have a stronger metallic character. The trend of metallic character increases from right to left and down a group in the periodic table, similar to the trend of electronegativity.

For example, Cs (cesium) will have the strongest metallic character among Cs, Ba, Fe, and Na because it is the furthest down and to the left in the periodic table. This means that it exhibits the highest degree of metallic character.

One of the most notable features of metallic solids is their high melting point. This is due to the strong metallic bonds between the metal ions and the sea of delocalized electrons. The melting point of a metallic solid is the temperature at which it transitions from a solid to a liquid state. Metallic solids have different melting points depending on the metal, but many of them have very high melting points.

In addition to their high melting points, metallic solids are also good conductors of electricity and heat. This is because the delocalized electrons in the metallic lattice are free to move and carry electrical charges or transfer heat energy. This property makes metallic solids widely used in the construction of electrical wires and cooking utensils.

Finally, it's worth noting that metallic solids can exhibit some interesting properties when mixed with other substances. For example, mixing a sodium and potassium mixture with water can turn the water into a metallic material with a golden color. This is due to the outermost electrons of the group 1 metals being borrowed by the water molecules.

Ductility and Malleability of Metallic Solids

Why is copper (Cu) a great choice of metal to make electrical wiring? It is because of the ability of copper to conduct electricity and also copper is ductile and can be molded into the shape of a wire. Metallic solids are considered malleable and ductile.

A malleable metal is a metal that can be battered into thin sheets. A ductile metal is a metal that can be molded into different shapes (like a wire) without breaking.

For example, gold can be hammered into thin gold leaves that are widely used in decorations. And, if that is not interesting enough, you can now even buy gold leaf flakes to use next time you cook your favorite dish!

Luster

Why do metals shine? Again, it all comes down to the delocalized electrons that metallic solids have in their structure.  Metals are lustrous (shiny) because the delocalized electrons can reflect off the light!

Metallic Alloys

When different metals are combined, they create a metallic alloy that also has metallic bonding. There are two main types of alloys: interstitial and substitutional.

Interstitial alloys are formed between metals with different radii, resulting in a more rigid lattice and less ductile and malleable alloy. Steel is a common example of an interstitial alloy, made up of carbon and iron.

Substitutional alloys are formed between metals with similar radii, allowing some of the atoms to be replaced by another metal atom. Brass is a common example of a substitutional alloy, made up of copper and zinc atoms.

In summary, metallic solids are compounds composed of metal atoms held together by metallic bonds. They possess unique properties such as luster, conductivity, malleability, ductility, and high melting points. Alloys are formed by combining different metals, resulting in new materials with their own set of properties.

References

AP Chemistry course and exam description, effective fall 2020. (n.d.). Retrieved April 8, 2022, from https://apcentral.collegeboard.org/pdf/ap-chemistry-course-and-exam-description.pdf?course=ap-chemistryBrown, T. L., LeMay, H. E., Bursten, B. E., Murphy, C. J., Woodward, P. M., Stoltzfus, M., & Lufaso, M. W. (2018). Chemistry: The central science (13th ed.). Harlow, United Kingdom: Pearson.Swanson, J. W. (2020). Everything you need to Ace Chemistry in one big fat notebook. Workman Pub.Malone, L. J., Dolter, T. O., & Gentemann, S. (2013). Basic concepts of Chemistry (8th ed.). Hoboken, NJ: John Wiley & Sons.https://media.nature.com/original/magazine-assets/d41586-021-02065-w/d41586-021-02065-w.pdf

Metallic Solids

What is a metallic solid?

A metallic solid is a compound made up of metal atoms being held together by metallic bonds. 

What structural units make up metallic solids?

Metallic solids are made up of positive ions (cations) and free-flowing electrons that are also known as a "sea" of delocalized electrons. 

What are the properties of metallic solids?

The properties of metallic solids are a high melting point, malleable, ductile and lustrous (shiny). Metallic solids are also good conductors of electricity and heat. 

What are metallic solids made of?

Metallic solids are compounds that are entirely comprised of metal atoms that are held together by metallic bonds. 

What are examples of metallic solids?

Examples of metallic solids include group 1 metals, group 2 metals, transitions metals, post-transition metals, lanthanides, and actinides.

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