The Amazing AtomThe Amazing Atom

AtomsAtoms

All matter is made of very tiny All matter is made of very tiny particlesparticlesThese These atomsatoms have the same have the same

properties as larger particles ofproperties as larger particles of

the matter havethe matter have

Parts of the AtomParts of the Atom

Subatomic ParticlesSubatomic Particles – smaller – smaller than an atom (parts)than an atom (parts)

ProtonProtonNeutronNeutronElectronElectron

Subatomic ParticlesSubatomic Particles

Protons (pProtons (p++))Positive chargePositive chargeEach one has a charge of +1Each one has a charge of +1Located in the nucleusLocated in the nucleusEach one has a mass of 1amu Each one has a mass of 1amu (atomic mass unit)(atomic mass unit)

Subatomic ParticlesSubatomic Particles

Neutrons (nNeutrons (n00))No chargeNo chargeLocated in the nucleusLocated in the nucleusEach one has a mass of 1amu Each one has a mass of 1amu (atomic mass unit)(atomic mass unit)

Subatomic ParticlesSubatomic Particles

Electrons (eElectrons (e--))Negative chargeNegative chargeEach one has a charge of -1Each one has a charge of -1Located in the space (cloud) Located in the space (cloud) around the nucleusaround the nucleus

Each one has a mass of about Each one has a mass of about 0.0006amu (atomic mass unit)0.0006amu (atomic mass unit)

The AtomThe Atom

The The nucleusnucleus has p has p++ and n and n00

Positively chargedPositively chargedThe The electron cloudelectron cloud has e has e--

Negatively chargedNegatively chargedThe number of protons equals the The number of protons equals the

number of electrons number of electrons in a neutral in a neutral atomatom

Periodic TablePeriodic Table

The periodic table gives us lots of The periodic table gives us lots of information about the elements.information about the elements.

1

H

Hydrogen

1.008

Atomic Number

Element Symbol

Element Name

Average Atomic Mass

Symbol PracticeSymbol Practice

For the element name, give the For the element name, give the symbol.symbol.

HeliumHelium

CarbonCarbon

SulfurSulfur

OxygenOxygen

MagnesiumMagnesium

Element PracticeElement Practice

For the symbol, give the element For the symbol, give the element name.name.

LiLi

NN

ArAr

AlAl

NaNa

Atomic NumberAtomic Number

Atoms of different elements are Atoms of different elements are differentdifferent

The number of protons in the nucleus The number of protons in the nucleus is the is the atomic numberatomic number of an element of an element

Atomic NumberAtomic Number

The The atomic numberatomic number identifies the identifies the elementelement

Like DNA Like DNA

for an elementfor an element

Proton PracticeProton Practice

Practice: How many protons are in Practice: How many protons are in each of the following elements?each of the following elements?

CarbonCarbon

Potassium Potassium

NitrogenNitrogen

Calcium Calcium

SiliconSilicon

ElectronsElectrons

Electrons give atoms their chemical Electrons give atoms their chemical propertiesproperties

In order for an atom to have a In order for an atom to have a neutral neutral chargecharge, it must have the same , it must have the same number of electrons as it has protons.number of electrons as it has protons.

Electrons = protons = atomic numberElectrons = protons = atomic number

Electron PracticeElectron Practice

Practice: How many electrons are in Practice: How many electrons are in each of the following elements?each of the following elements?

HeliumHelium

Chlorine Chlorine

NitrogenNitrogen

Aluminum Aluminum

BoronBoron

Mass NumberMass Number

All atoms have a All atoms have a mass numbermass numberWe can figure it out by rounding the We can figure it out by rounding the

Average Atomic Mass to the nearest Average Atomic Mass to the nearest whole numberwhole number

Mass number = protons + neutronsMass number = protons + neutronsNeutrons = Mass number – protonsNeutrons = Mass number – protons

Finding NeutronsFinding NeutronsExample: CarbonExample: CarbonRound the Average Atomic Mass to Round the Average Atomic Mass to

the nearest whole number: the nearest whole number:

12.01 rounds to 1212.01 rounds to 12How many protons in carbon?How many protons in carbon?

66Neutrons = Mass number – protonsNeutrons = Mass number – protons

Neutrons = 12 – 6 = 6Neutrons = 12 – 6 = 6

Neutron PracticeNeutron Practice

Practice: How many neutrons are in Practice: How many neutrons are in each of the following elements?each of the following elements?

OxygenOxygen

Chlorine Chlorine

ArgonArgon

Aluminum Aluminum

PhosphorusPhosphorus

Atomic Structure PracticeAtomic Structure PracticeFirst 25 Elements ActivityFirst 25 Elements Activity

IsotopesIsotopes

IsotopesIsotopes of an element have the of an element have the same number of protons, but different same number of protons, but different numbers of neutrons.numbers of neutrons.

There can be many isotopes of the There can be many isotopes of the same element.same element.

Atom Concept MapAtom Concept Map

IsotopesIsotopes

The The average atomic massaverage atomic mass of an of an element is determined by taking a element is determined by taking a weighted average of all of the weighted average of all of the isotopes of an element.isotopes of an element.

Isotope SymbolsIsotope SymbolsIsotopes of Isotopes of

elements have elements have symbols called symbols called isotopic symbols:isotopic symbols:

X = Element symbolX = Element symbol

A = Mass numberA = Mass number

Z = Atomic numberZ = Atomic number

XAZ

Isotope SymbolsIsotope Symbols

The isotope symbol for The isotope symbol for carbon would be:carbon would be:X = Element symbol = CX = Element symbol = C

A = Mass number = 12A = Mass number = 12

Z = Atomic number = 6Z = Atomic number = 6

C126

Isotopes of Candium ActivityIsotopes of Candium Activity

Quick CheckQuick Check

What is the atomic number of antimony?What is the atomic number of antimony?What is the symbol for tungsten?What is the symbol for tungsten?How many protons are in tin?How many protons are in tin?How many electrons are in potassium?How many electrons are in potassium?How many neutrons are in phosphorus?How many neutrons are in phosphorus?What is the mass number of lead?What is the mass number of lead?

Isotopic Symbol PracticeIsotopic Symbol Practice

The Bohr Model of the AtomThe Bohr Model of the Atom

BohrBohr developed the developed the “planetary”“planetary” model model of the atom, with electrons in orbits of the atom, with electrons in orbits around the nucleus.around the nucleus.

Each of these “orbits”, which we now Each of these “orbits”, which we now call call shellsshells, is an energy level for , is an energy level for electrons.electrons.

We start by filling the shell closest to We start by filling the shell closest to the nucleus firstthe nucleus first

The Bohr Model of the AtomThe Bohr Model of the Atom

Each of the shells can only hold a Each of the shells can only hold a certain numbercertain number of electrons of electrons11stst shell – maximum 2 electrons shell – maximum 2 electrons22ndnd shell – maximum 8 electrons shell – maximum 8 electrons33rdrd shell – maximum 18 electrons shell – maximum 18 electronsAdditional shells can hold more, but Additional shells can hold more, but

we do not have to go past the 3we do not have to go past the 3rdrd shellshell

The Bohr Model of the AtomThe Bohr Model of the Atom

Let’s see what that looks like for hydrogen:Let’s see what that looks like for hydrogen:

How many protons? How many electrons?How many protons? How many electrons?How many neutrons?How many neutrons?

The Bohr Model of the AtomThe Bohr Model of the Atom

Let’s see what that looks like for lithium:Let’s see what that looks like for lithium:

Build a Bohr DiagramBuild a Bohr Diagram

Bohr Model PracticeBohr Model Practice

Please do only the following elements Please do only the following elements on your Bohr Model Worksheet:on your Bohr Model Worksheet:

SodiumSodium HydrogenHydrogen

CarbonCarbon SiliconSilicon

OxygenOxygen ChlorineChlorine

ArgonArgon MagnesiumMagnesium

Human Bohr ModelHuman Bohr Model

Human Bohr Model.aviHuman Bohr Model.avi