Intro to ChemistryIntro to Chemistry

Atomic StructureAtomic Structure

What is an AtomWhat is an Atom

Smallest division of Smallest division of PURE MATTER PURE MATTER matter that still retains matter that still retains physical and chemical physical and chemical properties of that properties of that MatterMatter

First Proposed by the First Proposed by the Greeks 2400 years Greeks 2400 years ago: name means ago: name means indivisibleindivisible

Atomic StructureAtomic Structure

Atoms have 2 regionsAtoms have 2 regions

Nucleus- center of the Nucleus- center of the atom contains protons atom contains protons and neutronsand neutrons

Electron Cloud- Electron Cloud- empty space around empty space around atom which contains atom which contains the electronsthe electrons

Nucleus: Center of the AtomNucleus: Center of the Atom

Proton-Proton- + charged + charged particle: Atomic particle: Atomic NumberNumber

NeutronNeutron- has NO - has NO chargecharge

Protons + Neutron= Protons + Neutron= Atomic Mass of the Atomic Mass of the elementelement

Electron CloudElectron Cloud

Electron-smallest of Electron-smallest of the atomic particles; the atomic particles; has no weight. Orbits has no weight. Orbits around nucleus in around nucleus in electron cloudelectron cloud

How the atom “works”How the atom “works” Protons and Electrons “live” in Protons and Electrons “live” in

the postively charged nucleus the postively charged nucleus and make up the entire massand make up the entire mass

Electrons are negatively Electrons are negatively charged and occupy a charged and occupy a large amount of space large amount of space

surrounding surrounding the the nucleusnucleus

Atom “basics”Atom “basics”

Number of Protons = Number of ElectronsNumber of Protons = Number of Electrons

Neutrons have no charge so their number Neutrons have no charge so their number can change without changing the elementcan change without changing the element

Atomic Mass = # of Protons + # of Atomic Mass = # of Protons + # of Neutrons Neutrons

The Periodic TableThe Periodic Table

Unit II—Part 4Unit II—Part 4

The Father of the Periodic TableThe Father of the Periodic Table—Dimitri Mendeleev—Dimitri Mendeleev

Mendeleev was the first scientist to notice Mendeleev was the first scientist to notice the relationship between the elementsthe relationship between the elements Arranged his periodic table by atomic massArranged his periodic table by atomic mass Said properties of unknown elements could be Said properties of unknown elements could be

predicted by the properties of elements around predicted by the properties of elements around the missing elementthe missing element

Moseley later discovered that the periodic Moseley later discovered that the periodic nature of the elements was associated nature of the elements was associated with atomic number, not atomic masswith atomic number, not atomic mass

The Periodic TableThe Periodic Table

Column = Group or Family

18 columns on the Periodic Table

Row = Period

7 rows on the Periodic Table

What does the information in What does the information in the box tell me?the box tell me?

11

HH1.0081.008

Atomic Number = # of protons (and electrons

in its pure state)

Atomic Mass = # of

protons plus neutrons

Elemental Symbol

Metals, Nonmetals, and Metals, Nonmetals, and Semi-metalsSemi-metals

Metals are to the left of the stair-

step

Onlynonmetal on

the metal sideNonmetals are on the right of the stair-step

Semi-metals,

“metalloids,”

touch the stair-step

The Groups of the Periodic The Groups of the Periodic TableTable

Group 1 or (IA): The Alkali MetalsGroup 1 or (IA): The Alkali MetalsMost reactive metals on the PTMost reactive metals on the PTRarely found free in natureRarely found free in natureCharge of 1—1 valence electronCharge of 1—1 valence electron

Group 2 (or IIA) : The Alkaline Earth Group 2 (or IIA) : The Alkaline Earth MetalsMetalsStill quite reactiveStill quite reactiveCharge of 2—2 valence electronsCharge of 2—2 valence electrons

T he Groups of the Periodic T he Groups of the Periodic TableTable

Groups 3-12: Transition MetalsGroups 3-12: Transition MetalsFound freely and in compounds in Found freely and in compounds in

naturenatureCharge is usually 2 but can vary—Charge is usually 2 but can vary—

usually 2 valence electronsusually 2 valence electrons

Group 13 (or IIIA): Boron FamilyGroup 13 (or IIIA): Boron FamilyCharge is 3—3 valence electronsCharge is 3—3 valence electrons

The Groups of the Periodic The Groups of the Periodic TableTable

Group 14 or (IVA): The Carbon FamilyGroup 14 or (IVA): The Carbon FamilyContains elements that can form unusual Contains elements that can form unusual

bonds (carbon and silicon)bonds (carbon and silicon)Charge is +4 or -4—contains 4 valence Charge is +4 or -4—contains 4 valence

electronselectrons

Group 15 or (VA): The Nitrogen FamilyGroup 15 or (VA): The Nitrogen FamilyCharge is -3—contains 5 valence electronsCharge is -3—contains 5 valence electrons

The Groups of the Periodic The Groups of the Periodic TableTable

Group 16 (or VIA): The Oxygen Family Group 16 (or VIA): The Oxygen Family Also known as the chalcogensAlso known as the chalcogens Charge is -2—6 valence electronsCharge is -2—6 valence electrons

Group 17 (or VIIA): The HalogensGroup 17 (or VIIA): The Halogens Most reactive nonmetalsMost reactive nonmetals charge is -1—7 valence electronscharge is -1—7 valence electrons

Group 18 (or VIIIA): The Noble Gases (The Group 18 (or VIIIA): The Noble Gases (The Inert Gases)Inert Gases) Nonreactive Nonreactive Charge is 0—2 or 8 valence electronsCharge is 0—2 or 8 valence electrons

Special Rows on the PTSpecial Rows on the PT

Lanthanides

Actinides