How Atoms DifferHow Atoms DifferObjectives Covered in this Presentation:Objectives Covered in this Presentation:

7. Locate the three fundamental particles in the atom; 7. Locate the three fundamental particles in the atom; indicate the relative mass and charge of these particles. indicate the relative mass and charge of these particles. 8. Indicate what the atomic number and mass number of an 8. Indicate what the atomic number and mass number of an atom represent. atom represent. 9. Calculate the mass number when given the number of 9. Calculate the mass number when given the number of protons and neutrons. protons and neutrons. 10. Indicate which isotope is used as the standard for atomic 10. Indicate which isotope is used as the standard for atomic mass. mass. 11. Write the nuclear symbol for an atom. 11. Write the nuclear symbol for an atom. 12. Determine the number of protons, neutrons, and 12. Determine the number of protons, neutrons, and electrons when given the atomic number and mass number. electrons when given the atomic number and mass number. 13. Calculate average atomic mass from relative abundance. 13. Calculate average atomic mass from relative abundance. 14. Define isotope and identify which nuclides are isotopes 14. Define isotope and identify which nuclides are isotopes of the same element when given the atomic number and of the same element when given the atomic number and mass number of these nuclides. mass number of these nuclides.

Atomic structureAtomic structure

ProtonsProtons: positive particles in nucleus: positive particles in nucleus

NeutronsNeutrons: particle with no charge in the : particle with no charge in the nucleusnucleus

ElectronElectron: particle with negative charge : particle with negative charge orbiting the nucleus orbiting the nucleus

Subatomic Subatomic particlesparticles

QuarksQuarks: make up protons and neutrons : make up protons and neutrons

Six types: up, down, strange, charm, Six types: up, down, strange, charm, truth (top) and beauty (bottom)truth (top) and beauty (bottom)

((I am not making up those names, I am not making up those names, nuclear physicists can be weirdnuclear physicists can be weird.).)

Subatomic Particles Subatomic Particles (Cont)(Cont)

Other subatomic particles include Other subatomic particles include leptons, neutrino, tau, muon etc. leptons, neutrino, tau, muon etc.

Atomic SymbolsAtomic SymbolsSI symbols used internationally.SI symbols used internationally.

Based on Greek, Latin, a person’s Based on Greek, Latin, a person’s name, or location discovered.name, or location discovered.

Examples: Iron <Latin Ferrum>: FeExamples: Iron <Latin Ferrum>: Fe

Silver <Latin Argentum>: AgSilver <Latin Argentum>: Ag

Atomic SymbolsAtomic Symbols

11stst letter capitalized letter capitalized

22ndnd and 3 and 3rdrd letter lower case letter lower case

MUST be printed in traditional lettersMUST be printed in traditional letters

NO cursive NO cursive

Aluminum: Al not Aluminum: Al not AlAl

Cobalt: Co not CO or coCobalt: Co not CO or co

Atomic NumberAtomic Number

Equal to the number of protonsEqual to the number of protons

The number of protons for an element The number of protons for an element nevernever changes changes

Atomic NumberAtomic Number

In a In a stablestable atom, the number of atom, the number of protons = electronsprotons = electrons

The positive and negative charges are The positive and negative charges are equal and the overall charge is neutralequal and the overall charge is neutral

Nuclear ChargeNuclear Charge

If electrons are gained, the number of If electrons are gained, the number of electrons is greater than the number electrons is greater than the number

of protons and the charge is of protons and the charge is ____________________

Electric ChargeElectric Charge

If electrons are lost, the number of If electrons are lost, the number of electrons is less than the number of electrons is less than the number of

protons and the charge is protons and the charge is ____________________

Atomic MassAtomic Mass

May be noted as mass weight, or May be noted as mass weight, or atomic weightatomic weight

Equals: protons + neutronsEquals: protons + neutrons

Atomic MassAtomic Mass

Each proton and each neutron have Each proton and each neutron have an atomic mass of 1 amu. (Atomic an atomic mass of 1 amu. (Atomic mass units).mass units).

Electrons are so tiny (.00005 amu) Electrons are so tiny (.00005 amu) that their mass is negligible.that their mass is negligible.

Atomic Mass is an Atomic Mass is an AverageAverage

Remember: the number of protons for Remember: the number of protons for any element does not changeany element does not change

The number of neutrons does vary.The number of neutrons does vary.

Example: All carbon atoms have 6 Example: All carbon atoms have 6 protons. Most carbon atoms has 6 protons. Most carbon atoms has 6 neutrons, but very few have 8.neutrons, but very few have 8.

6P + 6N = 12 amu6P + 6N = 12 amu

6P + 8N = 14 amu6P + 8N = 14 amu

If you have 9 carbon atoms with 12 If you have 9 carbon atoms with 12 amu and 1 carbon atom with 14 amu, amu and 1 carbon atom with 14 amu, what is the average amu?what is the average amu?

If you have 9 carbon atoms with 12 If you have 9 carbon atoms with 12 amu and 1 with 14 amu, what is the amu and 1 with 14 amu, what is the

average amu?average amu?

9 atoms X 12 amu = 1089 atoms X 12 amu = 108

1 atom X 14 amu = 141 atom X 14 amu = 14

108 + 14 = 122108 + 14 = 122

122/10 =12.2 amu122/10 =12.2 amu

IsotopesIsotopes: atoms of the same element : atoms of the same element with different numbers of neutrons with different numbers of neutrons and slightly different amu.and slightly different amu.

The greater the number of protons for The greater the number of protons for an element, the greater the number of an element, the greater the number of isotopes.isotopes.

Periodic Table History:Periodic Table History: 1869 1869 Mendeleev created 1Mendeleev created 1stst Periodic Table. Periodic Table. He arranged it by atomic mass and He arranged it by atomic mass and successfully predicted unknown successfully predicted unknown elements.elements.

Modern Periodic Table: Modern Periodic Table:

Arranged by atomic numberArranged by atomic number

List element nameList element name

Element symbolElement symbol

Atomic numberAtomic number

Atomic massAtomic mass

PeriodsPeriods: (rows) all elements in the row : (rows) all elements in the row have the same number of energy have the same number of energy levelslevels

FamiliesFamilies: (column) have the same : (column) have the same number of valence electrons and number of valence electrons and oxidation state.oxidation state.

Valence electrons:Valence electrons: number of number of electrons in the outer most energy electrons in the outer most energy levellevel

Oxidation stateOxidation state: number of electrons : number of electrons needed to be gained or lost to have 8. needed to be gained or lost to have 8.

Using the periodic tableUsing the periodic table

Protons = ?Protons = ?

Using the periodic tableUsing the periodic table

Protons = atomic numberProtons = atomic number

Electrons = ?Electrons = ?

Electrons = number of protonsElectrons = number of protons

Neutron = ?Neutron = ?

Neutrons = atomic mass – atomic Neutrons = atomic mass – atomic numbernumber