Metallic Solids

Summary

This chemistry video by Mr. Andersen explores metallic solids, focusing on their unique properties like shininess, conductivity, and malleability. It delves into the electron sea model, which explains how free electrons contribute to metals' characteristics. The script also discusses alloy formation, including interstitial and substitutional alloys, using examples like steel, brass, and white gold to illustrate how different combinations can alter a metal's properties, such as preventing rust in stainless steel.

Takeaways

• 🌟 Metals are valued for their shiny appearance, electrical conductivity, ductility, and malleability, which are due to the electron sea model where electrons are free to move.
• 🔍 Metals can be bent and shaped, as seen with the creation of alloys like electrum, which is a mixture of gold and silver.
• 🛠 Alloys are formed by combining metals, which can be categorized into interstitial alloys, where smaller atoms fill gaps, and substitutional alloys, where atoms are replaced with different ones.
• 🔬 The electron sea model is fundamental to understanding the properties of metallic solids and their alloys, as it explains their shininess, conductivity, and malleability.
• 🌈 Metals can reflect light due to the presence of free electrons on their surface, which is why they appear shiny.
• ⚡ Metals are good conductors of both electricity and heat because of the high number of free electrons available for conduction.
• 💎 Ductility allows metals to be stretched into wires without breaking, showcasing their ability to deform under tension.
• 🔨 Malleability enables metals to be hammered into thin sheets, demonstrating the ease with which they can be shaped.
• 🔩 Alloys like stainless steel are created by adding specific atoms to iron, which changes its properties, such as making it rust-resistant.
• 🧩 Interstitial alloys, exemplified by steel, involve adding smaller atoms like carbon into the gaps within the metal structure to increase density and strength.
• 🔄 Substitutional alloys, such as brass, involve replacing one type of atom with another of similar size, resulting in a material with different properties from the individual metals.

Q & A

What are some of the unique properties of metallic solids?

Metallic solids have properties such as shininess, good electrical and thermal conductivity, ductility, and malleability, which are attributed to the presence of a 'sea' of free electrons that can move around easily.

Why are metals shiny?

Metals are shiny because they have free electrons on their surface that absorb some light and reflect a lot of it, giving them a lustrous appearance.

What is the electron sea model in the context of metallic solids?

The electron sea model describes the behavior of electrons in metals as a 'sea' of free electrons that can move around easily, contributing to the metallic properties such as conductivity and malleability.

What is an alloy and how does it relate to the electron sea model?

An alloy is a mixture of two or more metals or a metal and another element, which retains the electron sea model properties, allowing it to conduct electricity and heat, and be ductile and malleable.

How can metals be bent to our will?

Metals can be bent to our will due to their ductility and malleability, which allow them to be stretched or hammered into different shapes without breaking.

What is the difference between interstitial and substitutional alloys?

Interstitial alloys involve filling the gaps between metal atoms with smaller atoms, like carbon in steel. Substitutional alloys involve replacing one metal atom with another of similar size, such as zinc in brass.

Why can alloys have different chemical properties compared to their constituent metals?

Alloys can have different chemical properties because the added atoms can alter the electron configuration and interactions within the metal lattice, leading to new characteristics, such as stainless steel's resistance to rust.

What is the role of chromium and nickel in stainless steel?

Chromium and nickel in stainless steel help to prevent rusting by forming a passive layer that protects the iron from oxygen, thus reducing its interaction with the environment.

How does the electron sea model help in understanding the properties of metals?

The electron sea model helps in understanding the properties of metals by illustrating how the free movement of electrons contributes to their conductivity, malleability, and ductility.

What is the significance of the ability of metals to form alloys?

The ability of metals to form alloys is significant because it allows for the creation of materials with specific properties tailored for various applications, such as rust-resistant stainless steel or high-density steel.

How does the electron sea model explain the conductivity of metals?

The electron sea model explains the conductivity of metals by showing how the free electrons can move easily through the metal lattice, allowing for the flow of electric current.

Outlines

00:00

🌟 Metallic Solids and Their Properties

This paragraph introduces the topic of metallic solids, focusing on their unique properties such as shininess, electrical conductivity, ductility, and malleability. Mr. Andersen explains how metals can be bent and shaped, as well as mixed to form alloys like electrum and white gold. The electron sea model is presented as the underlying principle that gives metals their characteristic properties, with free electrons enabling metals to be shiny, conductive, and capable of forming alloys. The paragraph also touches on the different types of alloys, such as interstitial and substitutional alloys, and how they can alter the chemical properties of the resulting material, as exemplified by stainless steel's resistance to rust.

Keywords

💡Metallic Solids

Metallic solids refer to the solid form of metals, characterized by their ability to conduct electricity and heat, as well as their malleability and ductility. In the video, metallic solids are central to understanding the electron sea model, which explains their unique properties. The script mentions a 'big gold nugget' as an example of a metallic solid, highlighting its shininess and conductivity.

💡Electron Sea Model

The electron sea model is a concept that describes the behavior of electrons in metals as a 'sea' of free electrons that can move easily throughout the structure. This model is fundamental to the video's theme, explaining why metals are shiny, conductive, ductile, and malleable. The script uses this model to discuss how the properties of metals are derived from the movement of these free electrons.

💡Alloys

An alloy is a mixture of two or more elements, where at least one of them is a metal. The script discusses alloys in the context of metallic solids, explaining how they can be formed and the different types, such as interstitial and substitutional alloys. The video uses examples like 'electrum' (a mixture of gold and silver) and 'white gold' (a mixture of gold with other metals like nickel or palladium) to illustrate the concept of alloys.

💡Ductility

Ductility is a property of metals that allows them to be stretched into wires without breaking. The script mentions ductility as one of the key properties of metallic solids, using the example of pulling metals to stretch them out without causing them to break, which is a direct result of the electron sea model.

💡Malleability

Malleability is the ability of a metal to be hammered or rolled into thin sheets without rupture. The video script explains malleability in the context of metals being able to be 'hit and smoothed out,' which is due to the free movement of the nuclei within the electron sea, allowing the metal to deform without breaking.

💡Interstitial Alloys

Interstitial alloys are a type of alloy where smaller atoms are inserted into the spaces (holes) between the atoms of the metal. The script uses steel as an example of an interstitial alloy, where carbon atoms fill the holes in the iron lattice, increasing its density and making it a stronger metal.

💡Substitutional Alloys

Substitutional alloys occur when one type of atom in the metal is replaced by a different atom of a similar size. The video script explains this concept using brass as an example, which is made by substituting some of the copper atoms with zinc atoms, resulting in a material with different properties from the individual metals.

💡Stainless Steel

Stainless steel is a specific type of alloy that resists rusting due to the presence of chromium and often nickel. The script describes stainless steel as a combination of interstitial and substitutional alloying, where carbon is interstitial and chromium and nickel are substitutional, preventing the metal from interacting with oxygen and rusting.

💡Conduction

Conduction refers to the ability of a material to allow heat or electricity to pass through it. The video script explains that metals are good conductors because of the high number of free electrons available for movement, which is a direct result of the electron sea model.

💡Shininess

Shininess, or luster, is the property of a material that makes it reflect light, giving it a bright and polished appearance. The script explains that metals are shiny because of the free electrons on their surface, which absorb some light and reflect a lot of it, contributing to their visual appeal.

💡Electrum

Electrum is a historical alloy of gold and silver, mentioned in the script as an example of how metals can be mixed to form alloys with different characteristics. The creation of electrum demonstrates the ability to combine metals and alter their properties, which is a key point in the discussion of metallic solids and alloys.

Highlights

Metals have been historically fascinating due to their shiny appearance and electrical conductivity.

Metals can be bent and mixed to create alloys, such as electrum, which is a mixture of gold and silver.

Modern metallurgy allows for the creation of white gold by alloying gold with elements like nickel, magnesium, and palladium.

The electron sea model explains the properties of metallic solids, where electrons are free to move and contribute to their unique characteristics.

Metallic solids are ductile, allowing them to be stretched without breaking, and malleable, enabling them to be hammered into thin sheets.

Alloys can be categorized into interstitial, where smaller atoms fill the gaps within the metal structure, and substitutional, where atoms are replaced with different ones.

Brass is an example of a substitutional alloy, formed by combining copper with zinc.

The chemistry of alloys can differ significantly, as seen in stainless steel, which resists rust due to the addition of specific atoms.

In metallic bonding, it's not about individual bonds but the collective behavior of free electrons creating a 'sea' that influences properties.

Metals' shininess is attributed to the reflection of light from the free electrons on their surface.

Metals are good conductors of electricity and heat due to the abundance of free electrons and some mobility of the atoms.

The malleability of metals can be likened to a single large atom held together by a positive charge within and free electrons.

Alloys like electrum have been known for centuries, showcasing the ability to combine metals for different characteristics.

Interstitial alloys, such as steel, involve the insertion of smaller atoms like carbon into the metal structure to increase density.

Substitutional alloys, like brass, involve replacing atoms of similar size within the metal to create a new material with unique properties.

Stainless steel is a combination of interstitial and substitutional alloying, with carbon increasing density and chromium and nickel preventing rust.

Understanding the electron model is key to predicting the properties of metals and how they behave in different alloys.

Transcripts

Hi. It's Mr. Andersen and this is chemistry essentials video 24. It's on metallic solids. Like this

big gold nugget that was found. And so it's shiny. It conducts electricity. We've always

been fascinated with metals. And we also can bend metals to our will. In other words we

could mix gold with silver. And we get something called electrum. And today we can mix gold

with things like nickel, magnesium, palladium and we can get white gold. And so we can form

these alloys of metals. And so metallic solids are built on this electron sea model where

all those electrons are free. Able to move around. And that gives them lots of different

properties. They're shiny, good conductors. They're ductal. They're malleable. And they

can form these alloys. And that's all built on this idea that the electrons are free to

move about. They also can form alloys. The alloys that they form still are going to show

that electron sea model. And so they're still going to have those same properties. The alloys

can be broken down into interstitial alloys, when we're actually filling holes in the middle

itself with smaller atoms. Or they could be substitutional. Substitutional is when we're

going to replace one of the atoms in the metal with a different atom. An example could be

brass. And so the chemistry of alloys can sometimes differ. And so when we're making

stainless steel for example, we can make steel that doesn't rust because of the different

atoms that we're adding. And so remember in metallic bonding we shouldn't talk about just

one metallic bond. And that's because all of these electrons are moving around. These

free electrons. And as they do they push on each other and they create this sea of electrons.

And then the protons, the nuclei, are on the inside of that. Now they can still move around.

And it gives them those cool properties. Number one they're shiny. Why are metals shiny? It's

because they have all of these free electrons on their surface. And so as light hits it,

it's able to absorb some of that and reflect a lot of that light. If we're looking at they're

conduction, they can conduct both electricity and heat. And the reason why is that they

have high amounts of these free electrons. And the atoms have a certain amount of ability

to move. They're ductal. When you pull them, they're going to stretch out like this. They're

not going to break. They're not brittle. They also are malleable. We can hit them. And we

can smooth them out. And the reason why is you can think of it almost like one big atom

with all of these positive charges on the inside. And electrons holding them where they

are. And so these protons have these ability to move. Or these nuclei have these ability

to move. And also they can form alloys. And we've known this for years. That we can heat

different metals and we can get different characteristics from that. And so electrum

remember is an example of mixing gold with silver. But we can break these alloys into

basically two different parts. We can have what are called interstitial alloys. Interstitial

alloy, a great example would be steel. What we're doing when we're heating it up is we're

allowing carbon to fill the holes inside that iron. And what it does is increase the density.

And it's going to make it a better metal. Another type of metal is going to be substitutional

alloys. Substitutional alloys is when we're taking atoms that are about the same size.

So if we take copper, and we add zinc to it, then we can make brass. It's going to have

different characteristics than those metals by themselves. Stainless steel is formed in

the same kind of a way. If we take iron and we add atoms to it, we get a metal that looks

like that. Which type is that? Well it's a combination. It's interstitial because we're

going to have this carbon. But it's also going to be substitutional because we have chromium

and nickel. And what that's going to do is allow it to not interact with oxygen. It's

not going to allow it to rust. And so we can create a steel that doesn't rust as much over

time. Did you learn to compare the properties and constituents of elements in alloys. Those

atoms could either fit on the inside, interstitial alloys or it could be substitutional. And

then going back to metals. Do you understand this whole electron model? And how we can

use that to predict the different properties of metals? Well if you do, then you understand

metallic solids and I hope that was helpful.