Atomic Structure and Atomic Structure and the Periodic Tablethe Periodic Table

1. Students can describe the parts of an atom2. Students can read the element information

on the periodic table3. Students can describe the reactivity of

alkali metals4. Students can describe how various types

of bonding in different categories of materials effects their behavior

Atoms Atoms

smallest particle of an element that smallest particle of an element that has the properties of the elementhas the properties of the element

made of 3 basic subatomic particlesmade of 3 basic subatomic particles

there are now many more subatomic there are now many more subatomic particles – theoretical physicsparticles – theoretical physics

nucleusnucleus small, dense center of atomsmall, dense center of atom

contains almost all the mass of the atomcontains almost all the mass of the atom contains protons and neutronscontains protons and neutrons

Atomic Mass Unit (amu)Atomic Mass Unit (amu) metric unit to measure the mass of metric unit to measure the mass of

VERY small objects (particles)VERY small objects (particles) a unit to measure the mass of atomsa unit to measure the mass of atoms

Subatomic ParticlesSubatomic ParticlesName Protons (p or +) Neutrons (n) Electrons (e-)

Charge +1 No charge -1

Location in nucleus in nucleus in shells around nucleus

Mass ≈ 1 amu ≈ 1 amu ≈ 2000 x smaller

“Job” Determinesidentity ofelement

Supplies proper

mass to holdnucleus together

Determinesbonding/

how it reacts

Number

Subatomic ParticlesSubatomic ParticlesName Protons (p or +) Neutrons (n) Electrons (e-)

Charge +1 No charge -1

Location in nucleus in nucleus in shells around nucleus

Mass ≈ 1 amu ≈ 1 amu ≈ 2000 x smaller

“Job” Determines identity of element

Supplies proper mass to hold

nucleus together

Determines bonding/ how

it reacts

Number

Atomic # Atomic mass – atomic #

= # of

neutrons

Same as # of

protons

atomic numberatomic number whole number on periodic tablewhole number on periodic table number of number of protonsprotons in an atom of an in an atom of an

elementelement does NOT vary in an element – the same does NOT vary in an element – the same

in all atoms of an elementin all atoms of an element

# of protons# of protons

# of electrons# of electrons

atoms are neutralatoms are neutral

(+) = (-)(+) = (-)

# of protons = # of electrons# of protons = # of electrons

p = ep = e--

atomic mass (weight)atomic mass (weight) decimal number on the periodic table – decimal number on the periodic table – it it

is for all the atoms of the elementis for all the atoms of the element number of protons plus the number of number of protons plus the number of

neutrons neutrons – it’s an average on the table– it’s an average on the table weighted average of all the isotopes of weighted average of all the isotopes of

that elementthat element the mass of the mass of oneone atom is a whole number atom is a whole number

IsotopesIsotopes iso = sameiso = same atoms of the atoms of the same elementsame element with with

different numbers of neutronsdifferent numbers of neutrons have different atomic masses but the have different atomic masses but the

same atomic numbersame atomic number some are stable, some are radioactive some are stable, some are radioactive

(carbon-12 and carbon-14)(carbon-12 and carbon-14)

Free WriteFree Write

What do you know about:What do you know about: atomsatoms the periodic tablethe periodic table

Periodic TablePeriodic Table

How is the periodic table arranged?How is the periodic table arranged? arranged by increasing atomic numberarranged by increasing atomic number

rowsrows called periodscalled periods tells number of electron shellstells number of electron shells number them down the left side of the number them down the left side of the

periodic table – 1 through 7periodic table – 1 through 7

Periodic TablePeriodic Table

columnscolumns called families or groupscalled families or groups elements in same column have similar elements in same column have similar

chemical propertieschemical properties same number of valence electronssame number of valence electrons

IonIon

atom with a chargeatom with a charge atom has gained or lost electronsatom has gained or lost electrons gained egained e-- = (-) charge = (-) charge lost elost e-- = (+) charge = (+) charge

(+) ion = cation(+) ion = cation (-) ion = anion (-) ion = anion

Column 1Column 1

alkali metalsalkali metals want to give away one electronwant to give away one electron most reactive metalsmost reactive metals

Alkali metals on the show Alkali metals on the show brainiacbrainiac

BondingBonding

atoms achieve a stable number of atoms achieve a stable number of electrons (ionic and covalent)electrons (ionic and covalent)

involves valence (outer) electronsinvolves valence (outer) electrons

make compounds and/or solidsmake compounds and/or solids

Metallic BondingMetallic Bonding

All pure metals have metallic bonding and therefore exist as metallic structures.  Metallic bonding consists of a regular arrangement of positive ion cores of the metals surrounded by a mobile delocalized sea of electrons.

Metallic BondingMetallic Bonding Each atom donates its valence electrons to Each atom donates its valence electrons to

the whole the whole Atom therefore becomes a cation (here Atom therefore becomes a cation (here

called an called an ion coreion core) ) Donated electrons form an Donated electrons form an electron electron

cloudcloud surrounding all the ion cores surrounding all the ion cores Electron cloud binds all the ion cores Electron cloud binds all the ion cores

together by coulombic forces together by coulombic forces

Metallic BondingMetallic Bonding

Valence electrons are Valence electrons are delocalized:delocalized: Shared by all atoms in the material Shared by all atoms in the material Electrons are free to drift throughout the Electrons are free to drift throughout the

material material Provides unique properties only found in Provides unique properties only found in

metals metals shiny metallic luster shiny metallic luster good electrical and thermal conductivity good electrical and thermal conductivity many others ... many others ...

Metallic Bonds:  Mellow dogs with plenty of bones to go around

These bonds are best imagined as a room full of puppies who have plenty of bones to go around and are not possessive of any one particular bone.  This allows the electrons to move through the substance with little restriction.  The model is often described as the "kernels of atoms in a sea of electrons."

Ionic BondingIonic Bonding(ceramics and polymers)(ceramics and polymers)

Ionic BondsIonic Bonds: One big greedy thief dog!: One big greedy thief dog!

Ionic bonding can be best imagined as one big greedyIonic bonding can be best imagined as one big greedydog stealing the other dog's bone.  If the bonedog stealing the other dog's bone.  If the bonerepresents the electron that is up for grabs, then when represents the electron that is up for grabs, then when the big dog gains an electron he becomes negativelythe big dog gains an electron he becomes negativelycharged and the little dog who lost the electroncharged and the little dog who lost the electronbecomes positively charged.  The two ions (that's becomes positively charged.  The two ions (that's

wherewherethe name ionic comes from) are attracted very stronglythe name ionic comes from) are attracted very stronglyto each other as a result of the opposite charges.to each other as a result of the opposite charges.

Sodium lets Chlorine use its valance electron

Covalent BondingCovalent Bonding(Ceramics)(Ceramics)

Covalent BondsCovalent Bonds: Dogs of equal strength.: Dogs of equal strength.

Covalent bonds can be thought of as two or more dogsCovalent bonds can be thought of as two or more dogswith equal attraction to the bones.  Since the dogswith equal attraction to the bones.  Since the dogs(atoms) are identical, then the dogs share the pairs of(atoms) are identical, then the dogs share the pairs ofavailable bones evenly.  Since one dog does not haveavailable bones evenly.  Since one dog does not havemore of the bone than the other dog, the charge ismore of the bone than the other dog, the charge isevenly distributed among both dogs.  The molecule is evenly distributed among both dogs.  The molecule is

notnot"polar" meaning one side does not have more charge "polar" meaning one side does not have more charge

thanthanthe other. the other.

Polar Covalent BondsPolar Covalent Bonds: : Unevenly matched Unevenly matched but but willing to share.willing to share.

These bonds can be thought of as two or more These bonds can be thought of as two or more dogs thatdogs that

have different desire for bones.  The bigger dog hashave different desire for bones.  The bigger dog hasmore strength to possess a larger portion of themore strength to possess a larger portion of thebones.  Sharing still takes place but is an unevenbones.  Sharing still takes place but is an unevensharing.sharing.    In the case of the atoms, the electrons spend In the case of the atoms, the electrons spend more time on the end of the molecule near the atom more time on the end of the molecule near the atom with the greater electronegativity (desire for the with the greater electronegativity (desire for the electron) making it seem more negative and the other electron) making it seem more negative and the other end of the molecule seem more positive.end of the molecule seem more positive.

http://www.bbc.co.uk/scotland/education/bitesize/http://www.bbc.co.uk/scotland/education/bitesize/higher/chemistry/energy/bsp1_rev.shtml higher/chemistry/energy/bsp1_rev.shtml Read the 4 slides and take the quiz at the endRead the 4 slides and take the quiz at the end Patterns in the periodic tablePatterns in the periodic table

http://www.ewart.org.uk/science/structures/str13.htm http://www.ewart.org.uk/science/structures/str13.htm Ionic bonding Electron numbers ions and aionsIonic bonding Electron numbers ions and aions

http://www.ewart.org.uk/science/structures/str14.htm http://www.ewart.org.uk/science/structures/str14.htm Covalent bondingCovalent bonding

http://www.ewart.org.uk/science/structures/str7.htm http://www.ewart.org.uk/science/structures/str7.htm Structure of the atomStructure of the atom