I. What is an atom?

Atoms are the basic unit of matter All matter is made up of tiny atoms

Atom

Atoms are the building blocks of all matter

water

Molecule Atom

O

H H

Subatomic

Subatomic Particles (Draw this)

Proton Neutron Electron

Location in the Atom

Mass

Charge

Structure of an atom

There are 3 subatomic particles in an atom Proton Neutron Electron

THE PROTON

p+•Found in the nucleus

•Heavy: 1 amu

• Positive: +1

THE NEUTRON

N° • Located in the

nucleus.

•Heavy: 1 amu

• Neutral: 0 charge

o

NUCLEUS: DENSE/HEAVY BUT TINY PART OF ATOMFOUND IN CENTER OF AN ATOM

½ Football FieldOuter Edge

of Atom

Nucleus

50 End

Zone

Atomic Nucleus Summary

The nucleus is a dense area at the center of the atom Protons and neutrons are found in the

atomic nucleus

THE ELECTRON

• Found in the electron cloud

•Very light: 0 amu

•Negative: -1 charge

e-

Electrons

Electrons have a relatively small mass compared to protons and neutrons

Electrons are found far away from the nucleus in an area called the electron cloud

Electrons have a negative charge

How small is an atom?

Atoms are TINY!20 million hydrogen atoms would fit

inside the period at the end of this sentence.

You are made of billions and billions of atoms

http://htwins.net/scale2/

Protons

e-p+

N°

Neutrons Electrons

Positive+1

Neutral0

Negative-1

Nucleus is held together with

nuclear energy

Electron cloud is full of zipping electrons

http://www.youtube.com/watch?v=pV822HfqT44

Please complete the following tableProton Neutron Electron

Location in the Atom

Mass

Charge

Nucleus NucleusElectron

CloudHeavy1amu

Heavy1amu

Very Light 1amu

Positive +1

Neutral 0

Negative -1

ATOMS HAVE A NEUTRAL CHARGE (most of the time……)

When we talk about the atoms of elements on the periodic table, we usually assume they have the same number of electrons as they do protons, giving the atom a neutral charge (+1 and -1 = 0 charge)

So if the atomic number of an atom is 8, how many electrons do we have?

Neutrally charged Atoms will have the same number of electrons as protons

How can I tell which atom is which element?

Every atom of an element has anATOMIC SYMBOL- the letters representing the element Au, Ca etc.

ATOMIC NUMBER – the number of protons + in an atom. Each element has a unique atomic number

Example Carbon’s atomic number is 6, but Boron has an atomic number of 5ATOMIC MASS – the number of protons + plus neutrons 0 in an atom. Example Carbon’s atomic number is 6, but its atomic mass is 12 6 protons and 6 neutrons

N0P+e-

e-

e-

P+P+

What is the atomic number of this atom?

3

Review of Atomic Structure

What is the basic unit of matter? Atom

What are the 3 subatomic particles? Proton, Neutron, Electron

What’s the electrical charge of a proton? Positive (+)

What’s the electrical charge of a neutron? Neutral

What’s the electrical charge of an electron? Negative (-)

N0P+

e-e-

e-

P+P+

REMEMBER WHAT A PROPER ATOM LOOKS LIKE

0

+++

- -

-Name something wrong with this atom 0

+ +

-

+

--

0

What is wrong with this atom?

00

0 0

+

+

-

-+

0

0

What is wrong with this Atom?

Draw an atom CORRECTLY

2 protons, 1 neutron, 2 electrons