Atoms and Electron Diagrams

Do NowWhy are some objects or liquids more dense than others?

Objective-Understanding Atoms

Properties of Matter

MatterYou need to

remember that all MATTER is made up of Atoms.

Matter has mass and takes up space

Particles of MatterAtoms – The smallest particle of an Element

that retains the chemical properties of that element

Democritus – 400 BC, a Greek philosopher that coined the term “atomos which means “uncuttable, indivisible”

AtomsAll solids, liquids and gases are made up of

ATOMSTo be able to understand a little more about

an ATOM think of a Drop of WaterScientist’s say in 1 drop of water, there are 6

sextillion atoms- 6x10^21 (6000000000000000000000)

Do NowPlease list the 4 parts that make up an atom

Objective: SWBAT- Understand the structure of an Atom

What makes up a Atom?Atoms are

composed of three types of particles-(i.e-parts )

NeutronsProtonsElectronsThe Neutrons and

Protons are found in the Nucleus (which is the heart of the Atom

NeutronsAre found in the

nucleus of an atomNeutrons have no

charge, They are Neutral

The number of Neutrons will vary

Don’t be tricked its not a negative charge, think

Neutron=Neutral

ProtonsThey are also found

in the Nucleus of an atom

Protons have a positive (+) charge

Way to remember THINK Proton=Positive

Electrons Electrons are found on the outside of the nucleus. They orbit around the nucleus.

They have a negative charge (-).

The mass of an electron is very small

The more electrons the more negative an atom, the less electrons the more positive an atoms is.

Do Now- Name the 3 parts of the atom and the charges each give off

Electrons-They have a negative charge (-). Neutrons- The have neutral Protons- Have a positive

SWBAT- Know the differences between compounds and molecules

John Dalton -1802 - The Atomic TheoryAtoms can not be broken into smaller pieces – atoms

are like a solid marble (Not entirely accurate)

Compounds are always composed of whole number proportions of elements ie CO2 – Carbon dioxide, H2O – Water, C6H12O6 – Glucose, NaCl – Table Salt (this one is true also)

The basic particle of an Element is the Atom – H, He, Fe, etcThe basic particle of a Compound is the Molecule – a group of atoms that are chemicallybonded and act as a single unit until the bonds are broken: CO2, H2O, C6H12O6, NaCl

REVIEWhttps://www.brainpop.com/science/matterand

chemistry/atoms/

CompoundsA Compound is a molecule that at least 2 different elements.

MoleculeA molecule is formed when two or more

atoms join together chemically. A compound is a molecule that contains at least two different elements.

All compounds are molecules but not all molecules are compounds.

CompoundsMolecular hydrogen (H2), molecular oxygen

(O2) and molecular nitrogen (N2) are not compounds because each is composed of a single element.

Water (H2O), carbon dioxide (CO2) and methane (CH4) are compounds because each is made from more than one element. The smallest bit of each of these substances would be referred to as a molecule.

An atom refresherAn atom has three

parts:Proton = positiveNeutron = no chargeElectron = negative

The proton & neutron are found in the center of the atom, a place called the nucleus.

The electrons orbit the nucleus.

Picture from http://education.jlab.org/qa/atom_model_03.gif

Do Now: Is this a compound or a molecule? Explain why He4 …….CH4

He4= Molecule- single elementCH4= Compound- 2 or more elements

SWBAT- Explain why elements are sometimes called the building blocks of matter

Isotope

Periodic Table

8

OOxygen

16

Atomic Number:Number of protons and it is also the number of electrons in an atom of an element.Element’s Symbol:An abbreviation for the element.Elements Name

Atomic Mass/Weight:Number of protons + neutrons.

Atom ModelsThere are two models of the atoms we will

see in class.Bohr ModelLewis Dot Structure

Bohr ModelThe Bohr Model shows all

of the particles in the atom.

In the center is circles. Each circle represents a single neutron or proton. Protons should have a plus or P written on them. Neutrons should be blank or have an N.

In a circle around the nucleus are the electrons. Electrons should have a minus sign or an e.

++

-

-

Electrons have special rules….You can’t just shove all of the electrons

into the first orbit of an electron.Electrons live in something called

shells or energy levels.Only so many can be in any certain

shell. The electrons in the outer most shell

of any element are called valance electrons.

Nucleus

1st shell

2nd shell

3rd shell

Adapted from http://www.sciencespot.net/Media/atomsfam.pdf

So let’s try it….

How to draw a Lithium atomFirst, look at the Periodic TableSecond, determine the number of

protons (Look @ the atomic number)

Then determine the number of neutrons (Atomic mass – atomic number)

Then determine the number of electrons (Look @ the atomic number)

3

LiLithium

7

So let’s try it….3

LiLithium

7

+++

Protons = 3

Neutrons = 4(7-3=4)

-

-

-

Electrons = 3 2 in the 1st shell, 1 in the 2nd shell

Lewis Dot StructureThe Lewis Dot

Structure is a bit different from the Bohr model.

It only shows the element symbol and it’s outer most electron shell.

O• ••• •

•

+ +

+ +

+

++

+

-

-

- -

--

- -

How to… 1. Write the

symbol.2. Start on the

right hand side, working your way clockwise around the symbol.

3. Try Lithium