3A+Elaina+Lam


 * Sorry! The video is longer than 3 minutes, But i'm interesting to look at, so don't worry :)**
 * Also a note, at the end where i'm summing up and pointing with my fingers the directions, i'm pointing from low to high melting points, just incase you didn't understand! If you don't understand what i'm saying its all basically underneath the vid...**

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“Hi everyone! I hope you’re all ready for chemistry!”
 * Introduction**

“So in this video, I’ll hopefully be explaining the trends in the melting and boiling points of elements in the periodic table for you”

“I decided to do it as a video, because if I was me, I would be too lazy to read, so instead watch me!”

“To start off with, if you guys don’t already know, this is a periodic table”
 * Explain Periodic Table**

“With this cool one I found on the internet, I’ll start off explaining the basics of it”

So the periodic table is split into 3 basic groups, Metalloids, Non-Metals and Metals, simple.

And from the 2 groups Non-Metals and Metals there are subgroups.

In the non-metals we have **Noble Gases, Halogens and Other non metals**

In the metals we have **Alkali Metals, Alkali Earth metals, Lanthanoids, Actinoids, Transition metals and Post transition metals.**

The elements are split into those three groups based on their bond type.
 * Bonding**

Not like 007, but for instance, Elements in the non-metal group show covalent bonding, while metals present metallic bonding.

Metalloids are different though. This is because they have properties of both a metal and a non-metal element, so they can’t be put into just one group.

As a rule of thumb, **non-metals** have **low melting and boiling points** and Metals have **high melting and boiling points.**

To understand why this is, you need to know about a few things, Atomic radii, Atomic structure and how melting and boiling works
 * Metal trend**


 * 1) Melting and boiling occurs when the bonds in the element must be broken. Energy is used to break these bonds.
 * 2) In a solid the atoms are all close together and it takes a lot of energy to break it apart. For this purpose the energy we’re using to break apart the atoms is heat.


 * 1) When you go down the periodic table, the amount of protons, neutrons and electrons increase in the element’s atomic structure.
 * 2) Before we talked about metallic and covalent bonds, and as we know group 1 alkali metals have metallic bonds.
 * 3) The strength of the metallic bond is from the attraction between the nucleus, which are the protons and neutrons, and the electrons around it, also known as delocalized electrons.
 * 4) As you travel down the group the atoms become larger so the distance between the nucleus and the electrons increases meaning the attraction between the two is weaker.
 * 5) So if you were following what I was saying before, you can get that when you go down the group 1 alkali metals where the atomic radii gets larger so the bonds are weaker, so less energy, in this case heat, is needed to melt then boil the element.
 * 6) This shows how the element’s melting point is inversely proportional to the atomic radii for metals.


 * Non-metals**
 * 1) With non-metals the trend is different compared to the metals. Instead of melting and boiling points decreasing and you travel down the group, they increase as you go down the group. There are a number of reasons for this one as well. Atomic radii and Van Der Waals forces.


 * 1) To first understand VDW’s forces you have to understand that non-metal molecules have intermolecular attraction. That means there are attractions between two nearby molecules.


 * 1) So we know that electrons are always moving right? So that means for even just a tiny bit of time one side will have more electrons than the other, making one side more negative and one side more positive.


 * 1) We also know that when an atom that's charged comes close to another atom that's not charged it will induce a charge on it, making an intermolecular attraction with the two atoms.


 * 1) Why are Van Der Waals’ forces so important? That’s because they relate to atomic radii. With non-metals, the larger the atomic radii the stronger the intermolecular attraction, this is because, as we talked about in the metals part, there are more electrons, meaning more induced charges, which equals a stronger attraction.


 * 1) With a stronger attraction, meaning stronger bond, it takes more energy to break the bond apart, meaning you need a higher temperature to melt and boil the element.


 * Transition metals**
 * 1) Okay so for the transition metals, the melting and boiling point increases as you move from the left going to the right of the table then once reaching it’s peak, the melting and boiling point decreases.
 * 2) With technetium and manganese, in period 5 and 4 respectively, being an exception.
 * 3) Tin is also an exception as it has a higher melting and boiling than you would think.


 * Non-metals (periods)**
 * 1) Last but not least, you’ve got the period 2 and 3 non-metals, excluding Carbon because, well when I want diamonds it won’t give me any. (no, it’s because it doesn’t have a liquid phase at atmospheric pressure).
 * 2) Similar to transition metals except it doesn’t peak then decrease gradullay it just decreases all the way through, meaning nitrogen would have a higher melting point than neon, same with phosphorus having a higher melting point than argon.
 * 3) Again we exclude sulphur because it’s smelly. (no it’s just an exception, with a higher melting point than we would expect)

Bibliography http://www.creative-chemistry.org.uk/alevel/module1/trends4.htm http://www.ptable.com/