Inside matter.But, what is matter made of?

Long time ago, Greeks wonder about matter composition. As a rock breaks into smaller fragments, what would be the smallest fragment achievable?

To these early Greeks, matter could not be continuously broken down and divided indefinitely.

Grinding matter.

Rather, there was a basic unit or building block that was indivisible and foundational to its structure.

Atoms.

Atomos in Greek means indivisible.

An atom is a fundamental piece of matter.

All matter is made up of this.

A lithium atom.

Atoms.

An average measurement of an atom size has been stimated.

For example, the smallest atom that exists, is HYDROGEN.

Atoms.

Hydrogen size = 0’000 000 000 1 m

Atoms were thought as spheres of matter. Littles pieces of a bigger body.

But there were several problems with this model… Electric phenomena was not explainable.

Atoms.

To explain attraction and repulsion between bodies, scienctists resort to electric charge, a property of matter.

◦ Electric charge causes electric phenomena: attraction and repulsion.

◦ There are two different types of electric charge: positive and negative.

After the experiment.

After the experiment.

Think about magnets. And wait.

https://www.youtube.com/watch?v=-4Us5PTb4J8

History of the Atom (Dalton, Thomson, Rutherford,

and Bohr Models)

The simplest atom is made up of three main particles: ◦ Proton positively charged.◦ Neutron no charge.◦ Electron: negative charge.

They are organized in ◦ A nucleus: protons (+) and neutrons.(0)◦ Electrons (-) around the nucleus.

So…

Subatomic particle Proton Neutron Electron

Charge + 0 -

Mass ±hydrogen atom mass ± proton mass ±hydrogen

mass x 2.10-3

Where are they? Nucleus Nucleus Around nucleus

There is nothing but empty space between the nucleus and electrons.

Matter that surrounds us is, in general, neutral (we don’t get a discharge every single time we touch something).

So, a neutral atom must havepositive charges = negative charges

In other words,number of protons = number of

electrons

Neutral o not neutral. That’s the question.

Neutral o not neutral. That’s the question.

¡BUT! Sometimes atoms

are charged.

Because of proximity of other atoms or other circumstances, like electric discharges, high temperatures…

Atoms like to be stable. They feel most stable when their outer electron shells are full. They become full when they have eight electrons in them.

This is called the octet rule.

They get eight electrons by either borrowing some from or giving some to another atom

Ions

An ion is an atom that has gained or lost one or more electrons and therefore has a negative or positive charge.

◦ A cation is an atom that has lost an electron and therefore has more positive protons than negative electrons, so it is positively charged.

◦ An anion is an atom that has gained an electron and is negatively charged.

Ions

Ion

5

A chemical element represents all the atoms of the same type in nature. An element is a substance consisting of atoms which all have the same number of protons.

Chemical elements

Although an element's atoms must all have the same number of protons, they can have different numbers of neutrons and hence different masses.

Isotopes

Isotopes

When atoms of the same

element have different

numbers of neutrons, they

are called isotope

s.

Pure substances

Simple substances

Atoms (noble gases) Molecules

(oxigen, nitrogen)

Otrher clusters (metals, graphite)

Compounds

Molecules (water)

Ionic crystals(cooking salt)

Same element

Different elements

He

http://www.nyu.edu/pages/mathmol/textbook/at

http://profmattstrassler.com/articles-and-posts/particle-physics-basics/the-structure-of-matter/the-nuclei-of-atoms-at-the-heart-of-matter/oms.html

http://education-portal.com/academy/lesson/ions-predicting-formation-charge-and-formulas-of-ions.html

http://www.wikihow.com/Find-Electrons

https://www.physicsforums.com/threads/whats-inbetween-an-atoms-nucleus-and-electrons.230889/

http://chemwiki.ucdavis.edu/Physical_Chemistry/Atomic_Theory/Atomic_Theory

Just for educational purpose.

Sources.