KaiserScience

Home » Chemistry » Periodic table » Metals and non-metals

Metals and non-metals

Advertisements

Metals are good conductors of electricity, and of heat.

Electricity is the conduction of valence electrons from one atom to another

Metals conduct heat:

The atoms in a substance are always vibrating. When heat is applied to a substance the heat energy is given to the atoms and they vibrate and move faster and so their kinetic energy increases.  The vibrating atoms bump into neighboring atoms and pass on their kinetic energy. These atoms then pass on their kinetic energy to atoms close to them and so on. In this way the heat energy moves through the substance.

Conduction takes place in solids, liquids and gases, but works best in solids as their atoms/molecules are located closer together.
Metals are the best solids for conducting heat.
Metals have tightly packed atoms which can easily pass on their kinetic energy and also have free moving electrons.
These electrons can move from the hot part of the metal to the colder part transferring the energy more quickly.

Poor conductors or insulators do not possess free moving electrons.

– http://www.passmyexams.co.uk/GCSE/physics/conduction-heat-transfer.html

Heat conduction GIF

2. Fresh cut metal has a high luster/sheen.

Lustre or luster is the way light interacts with the surface of a crystal, rock, or mineral. The word traces its origins back to the latin lux, meaning “light”. A range of terms are used to describe lustre, such as earthy, metallic, greasy, and silky.

3. Most metals are solid at room temperature.

4. Ductile – metals can be drawn into wires.

Here, reddish copper is inside a steel cup, with a small hole. Pressure is applied to the copper – and a small amount is pushed out through the hole. A tool grabs this exposed copper, and slowly pulls. As it pulls, more and more copper is drawn out in a tube.

5. Malleable – can be hammered into thin sheets without breaking

The ability to deform under compressive stress;

The material’s ability to form a thin sheet by hammering or rolling

 

6. Metals deform because atoms can slide past each other, while still maintaining bonds. How is this possible?

A metallic bond is a lattice of positive ions, immersed in a sea of electrons. The ions here are entire atoms: the nucleus, and many of it’s electrons, still tightly bound to their parent atom.

The ‘sea’ around them are the valence electrons: valence electrons are the outermost electrons. They are not tightly bound to their home atom.

Valence electrons freely flow through solid metal, as if they are a gas!

sea of electrons in metal

image from Francisco Esquembre , Universidad de Murcia; Maria Jose Cano; lookang http://weelookang.blogspot.sg/

Here’s an example of electrons being pushed through the metal by an electric current
(that’s why they are all moving in the same direction)

Metallic bonds moving GIF

If an object (like a hammer) slowly pushes into the metal then the atoms are pushed – yet the atoms are still bonded to each other through this sea of valence electrons.

Metallic bonds moving malleable GIF

reasons malleable metal deform

Section 2: Non-metals

1. Non-metals are not good conductors of electricity or heat

2. Do NOT have a high luster/sheen

3. Most are gases at room temp

4. NOT ductile – can NOT be drawn into wires

5. NOT malleable – can NOT be hammered into thin sheets without breaking.
This means that they are BRITTLE

 

Mixed properties: Metalloids

1. Have properties in-between those of metals and non-metals

2. Under specific conditions, a metalloid may behave like a metal or non-metal

3. We can easily control how a metalloid behaves by changing the conditions:

Just evenly mix a small amount of another element into the metalloid

By controlling how much of this new element we add, we can control the exact properties of the metalloid. This makes them useful in creating semiconductors.

 

Articles about metals

Crystals in metals: Why do metals have the properties that they have?

 

Hydrogen is in its own special category

H is neither a metal or a non-metal. It has it’s own unique behavior.
Here we see two H atoms coming together and bonding.

Hydrogen covalent bonding

1. colorless, odorless, nonmetallic, tasteless

2. highly combustible

3. Diatomic gas -> molecular formula H2

4. the lightest element

5. Most abundant chemical element: makes up 75 % of the Universe’s mass

Learning Standards

TBA

 

Advertisements

1 Comment

Leave a Reply

Please log in using one of these methods to post your comment:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

w

Connecting to %s

%d bloggers like this: