Updated October 2006 Created by C. Ippolito September 2006 Elements, Atoms, and the Periodic Table Unit Objectives: 1.Identify the names, symbols and

Updated October 2006Updated October 2006Created by C. IppolitoCreated by C. Ippolito

September 2006September 2006

Elements, Atoms, and the Elements, Atoms, and the Periodic TablePeriodic Table

Unit Objectives:Unit Objectives:1.1. Identify the names, symbols and origin of chemical elements;Identify the names, symbols and origin of chemical elements;2.2. Appreciate relative abundance of various elements;Appreciate relative abundance of various elements;3.3. Identify the different kinds of elements represented in the Identify the different kinds of elements represented in the

periodic table;periodic table;4.4. Recognize the major properties used to distinguish the Recognize the major properties used to distinguish the

different types of elements;different types of elements;5.5. Appreciate the historical development of the atomic theory;Appreciate the historical development of the atomic theory;6.6. Explain and describe the atomic structure of elements and Explain and describe the atomic structure of elements and

how it relates to their individual propertieshow it relates to their individual properties



Elements: Ancient and Modern Elements: Ancient and Modern TheoryTheory

• Robert Boyle – 1661 - “The Sceptical Chymist”

• Element– Substance that cannot be broken into simpler

substances

• Compound– Formed when two or more elements combine

• Antoine Lavoisier (1743-1794)– 1789 – “Elementary Treatise on

Chemistry”• Identified 33 “elements”



Chemical SymbolsChemical Symbols

• alchemists used secret codes– signs for known elements

• shorthand used to represent elements– JJ Bersalius

• each element is represented a one or two letter symbol with the first letter always capitalized

• symbol derived from first letter of name, if already assigned take a second letter from name



Chemical Names and SymbolsChemical Names and Symbols

• English named– aluminum (Al)– argon (Ar)– arsenic (As)– carbon (C)– calcium (Ca)

• Honorary named– Curium (Cm)– Californium (Cf)

• Latin named– gold [aurum] (Au) – iron [ferrum] (Fe)– lead [plumbum] (Pb) – mercury [hydragyrum] (Hg) – silver [argentum] (Ag)– sodium [natrium] (Na)– tin [stannum] (Sn)

• German named– tungsten [wolfram] (W)



Abundant and Rare ElementsAbundant and Rare Elements

• 11 elements form 99% of earth crust

- oxygen- silicon- aluminum- iron- calcium- sodium

- potassium- magnesium- hydrogen- titanium- chlorine



Periodic Table of ElementsPeriodic Table of Elements

• metals • metalloids • nonmetals



Organization of Periodic TableOrganization of Periodic Table

• Rows– form periods

• Columns– form groups or families

• Classroom Table– REDRED

• gaseous elements

– BLUEBLUE• liquid elements

– BLACKBLACK• solid elements



MetalsMetals• Physical Properties – solid, except Hg

– Conductivity• good conductors of heat and electricity

– Luster• shiny surface

– Malleability• may be hammered or rolled

– Ductility• may be drawn into wires

– Hardness• varies

– hard – Cr, Fe, Mn– soft – Au, Pb, Na



NonmetalsNonmetals• Physical Properties – solid, liquid, gas

– Conductivity• poor conductors of heat and electricity

– Luster• NONO, dull surface

– Malleability• NONO, brittle – crumble when hit

– Ductility• NONO

– Hardness• NONO

– carbon (diamond) exception



MetalloidsMetalloids

• some properties like metals others like nonmetals– semiconductors



Early Atomic StructureEarly Atomic Structure• DemocritusDemocritus

– Atomic Theory of MatterAtomic Theory of Matter• all matter could be divided into tiny

indivisible particles called atomsatoms • different types of atoms existed for each

different type of material• not based on experimental evidence

• AristotleAristotle– Continuous Theory of MatterContinuous Theory of Matter

• all matter was continuous and always could be divided into smaller parts without end



Law of Conservation of MassLaw of Conservation of Mass• Antoine LavoisierAntoine Lavoisier

– Father of Modern ChemistryFather of Modern Chemistry• quantitatively measured mass

of reactants and compared it with mass of products

• found mass remained constant– Law of Conservation of MassLaw of Conservation of Mass

• matter can be changed but cannot be created nor destroyed

• combustion combines elements with oxygen



Law of Definite ProportionsLaw of Definite Proportions• Joseph ProustJoseph Proust

– regardless of where a substance came from or how large the sample

– specific substances always contained elements in the same ratio by mass

• Law of Definite ProportionsLaw of Definite Proportions



Dalton’s Atomic TheoryDalton’s Atomic Theory

• John Dalton– postulates to explain Lavoisier’s and

Proust’s findings1. Matter made of small particles (atoms)2. Atoms are indestructible. Cannot be

created or destroyed in chemical or physical changes.

3. Atoms of same element are identical, have the same mass.

4. Atoms of different elements are different, have different mass

5. Compounds form by combining atoms of different elements



Parts of the AtomParts of the Atom

• in the late 1800’s experiments show that atoms are made of smaller particles– ElementaryElementary or Subatomic ParticlesSubatomic Particles

• proton proton – positive charge, mass = 1 amu, in nucleus– positive charge, mass = 1 amu, in nucleus• electron electron – negative charge, mass = 1/1837 amu, outside nucleus– negative charge, mass = 1/1837 amu, outside nucleus• neutron neutron – neutral charge, mass = 1 amu, in nucleus– neutral charge, mass = 1 amu, in nucleus



Elements and IsotopesElements and Isotopes

• Isotope– atoms of the same element that have different mass

• same atomic number– same number of protons and electrons

– same behavior

• mass differs because the atoms have different numbers of neutrons

• Isotopes of Hydrogen– Protium 1

1H

– Deuterium 21H

– Tritium 31H



Atomic MassesAtomic Masses

• for an individual atom is a whole number– atomic mass = # of protons + # of neutrons

• for an element it is the average of the atomic masses of all existing isotopes– in periodic table it is a decimal value

• Calculation of Element Atomic Mass– (isotope mass)x(abundance) = mass contribution– add mass contributions of all isotopes– resulting sum is the average atomic mass



MoleMole

• the mole is a fixed amount of particles– 1 mole = 6.022 x 1023 pieces– this number is N or Avogadro’s Number

• named in honor of an Italian chemist

• the concept of the mole allows us to set up a relationship between the immeasurable masses of atoms (in amu) and measurable amounts of a substance (in grams)– 1 mole of amu’s = 1 gram

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Updated October 2006 Created by C. Ippolito September 2006 Elements, Atoms, and the Periodic Table Unit Objectives: 1.Identify the names, symbols and