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Matter Matter & &

the Atomthe Atom

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MatterMatterThe term matter describes all of the

physical substances around us.:

Your table,your body,

a pencil,

water, THE UNIVERSE.

Matter has mass and takes up space (volume).

It is made up of different kinds of atoms.

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Matter includes things that can be seen,

tasted,

smelled, or touched.

Matter does not include heat, sound, or light.Matter does not include heat, sound, or light.

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What is matter made of? What is matter made of?

Models are for things that are too small or too large.

Models explain data or facts. So, they are theories.

Modern Model of the AtomThe Electron Cloud

Modern Model of the AtomThe Electron Cloud

Is sometimes called the wave model.

Has a spherical cloud of varying density.

Varying density shows where an electron is more or less likely to be.

Is sometimes called the wave model.

Has a spherical cloud of varying density.

Varying density shows where an electron is more or less likely to be.

What do we now think atoms are made of?What do we now think atoms are made of?

Electrons:Electrons:•Are tiny, light electrical particles that are negative (-).Are tiny, light electrical particles that are negative (-).•Move around the outside of the nucleusMove around the outside of the nucleus..

Electrons:Electrons:•Are tiny, light electrical particles that are negative (-).Are tiny, light electrical particles that are negative (-).•Move around the outside of the nucleusMove around the outside of the nucleus..

ProtonsProtons::•Are much larger and heavier than electrons.Are much larger and heavier than electrons.•Have a positive charge (+).Have a positive charge (+).•Are located in the nucleus.Are located in the nucleus. 

ProtonsProtons::•Are much larger and heavier than electrons.Are much larger and heavier than electrons.•Have a positive charge (+).Have a positive charge (+).•Are located in the nucleus.Are located in the nucleus. 

Neutrons:Neutrons: Are large and heavy like protons.Are large and heavy like protons. Have no electrical charge.Have no electrical charge. Are located in the nucleus of the atom.Are located in the nucleus of the atom.

Neutrons:Neutrons: Are large and heavy like protons.Are large and heavy like protons. Have no electrical charge.Have no electrical charge. Are located in the nucleus of the atom.Are located in the nucleus of the atom.

An Atom is a Basic An Atom is a Basic Building Block, so it’s an Building Block, so it’s an

Element!Element!

An Atom is a Basic An Atom is a Basic Building Block, so it’s an Building Block, so it’s an

Element!Element! Each element has a different number of protons.

The number of protonprotons is also called

the atomic number.the atomic number.

So,

atomic #atomic # = # of protons# of protons

The atomic #The atomic #= FingerprintFingerprint

Each element has a different number of protons.

The number of protonprotons is also called

the atomic number.the atomic number.

So,

atomic #atomic # = # of protons# of protons

The atomic #The atomic #= FingerprintFingerprint

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•Every _______ Every _______ has its own has its own atomic number.atomic number.

•Every _______ Every _______ has its own has its own atomic number.atomic number.

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So what’s with atomic mass?

So what’s with atomic mass?

Imagine trying to measure the mass of something so small that you cannot see it!

Imagine trying to measure the mass of something so small that you cannot see it!

Scientists use theScientists use the amuamu, , or or atomic mass unitatomic mass unit, ,

to measureto measure massmass..

One One amuamu = the = the mass of one proton and neutronmass of one proton and neutron, , but the but the electronelectron is is so smallso small,, it is it is 1/1,8361/1,836 amu! amu!

So, cut out theSo, cut out the electronelectron in the calculationin the calculation: :

the mass of protons + neutronsthe mass of protons + neutrons = = atomic massatomic mass..

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How are atomic mass and atomic number different?

Does it matter?

How are atomic mass and atomic number different?

Does it matter?The atomic numberatomic number can be found can be found above the element’s name on the above the element’s name on the periodic table. periodic table. It is the number of protons.It is the number of protons.

The atomic massatomic mass is both the protons and the neutrons together. Round it..Atomic massAtomic mass - Atomic numberAtomic number == the # of neutrons. If you know one of the three numbers, can

you figure out the others?

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The atomic number of an The atomic number of an element never changes. This element never changes. This is its fingerprint. is its fingerprint.

But, atoms of the same But, atoms of the same element mayelement may notnot all have all have the the samesame numbernumber of of neutronsneutrons..

This means that these atoms This means that these atoms may have a different atomic may have a different atomic mass.mass.

The atomic number of an The atomic number of an element never changes. This element never changes. This is its fingerprint. is its fingerprint.

But, atoms of the same But, atoms of the same element mayelement may notnot all have all have the the samesame numbernumber of of neutronsneutrons..

This means that these atoms This means that these atoms may have a different atomic may have a different atomic mass.mass.

If Element = Different Atomic Mass than If Element = Different Atomic Mass than says on Periodic Table, it’s Called says on Periodic Table, it’s Called

IsotopeIsotope

If Element = Different Atomic Mass than If Element = Different Atomic Mass than says on Periodic Table, it’s Called says on Periodic Table, it’s Called

IsotopeIsotope

Isotope :Isotope : An Element that Has a Different Atomic Mass An Element that Has a Different Atomic Mass than What Appears on the Periodic Chart.than What Appears on the Periodic Chart.

It Even Has a Different Name.It Even Has a Different Name.

Isotope :Isotope : An Element that Has a Different Atomic Mass An Element that Has a Different Atomic Mass than What Appears on the Periodic Chart.than What Appears on the Periodic Chart.

It Even Has a Different Name.It Even Has a Different Name.

IsotopesIsotopes = Element Element VariationsVariations

IsotopesIsotopes = Element Element VariationsVariations

If an isotope has a different atomic masses, If an isotope has a different atomic masses,

and you know its atomic number, and you know its atomic number,

what can you figure out ?what can you figure out ?

If a nucleus has too many or too few neutrons, it becomes unstable. It releases radiation and decays.This means the electrons can be broken down and released.

Mass # - Atomic # = # of NeutronsMass # - Atomic # = # of NeutronsMass # - Atomic # = # of NeutronsMass # - Atomic # = # of Neutrons

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Carbon-14 dating, or radiocarbon dating, uses

the amount of carbon-14 in a substance to calculate

its age.

Carbon-14 dating, or radiocarbon dating, uses

the amount of carbon-14 in a substance to calculate

its age.

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Ions are Atoms Seeking BalanceIons are Atoms Seeking Balance

An atom that carries an electrical charge is called an ion.

If the atom loses electrons, the atom becomes positively charged (more protons = + charge). What if it gains electrons? (more electrons = - charge)

An atom that carries an electrical charge is called an ion.

If the atom loses electrons, the atom becomes positively charged (more protons = + charge). What if it gains electrons? (more electrons = - charge)

Ions Seek PartnersIons Seek PartnersHint:Hint:

All electrons have a negative chargenegative charge.

How is this ion How is this ion positive?positive?

How is this ion How is this ion negative?negative?

Hint:Hint:

All electrons have a negative chargenegative charge.

How is this ion How is this ion positive?positive?

How is this ion How is this ion negative?negative?

Helium Atom

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How much do you know about atoms?

How much do you know about atoms?

AtomsAtomsElectrons Electrons

ProtonsProtonsAtomic NumberAtomic Number

NeutronsNeutronsElements Elements Atomic Atomic

MassMassIsotopesIsotopes

IonsIons