Atomic Theory

Atomic TheoryAtomic Theory

John DaltonJohn Dalton Four Part Theory adopted as basis for the Four Part Theory adopted as basis for the

Modern Atomic TheoryModern Atomic Theory

1.1. All things are made of atomsAll things are made of atoms

2.2. Similar atoms are similar and different atoms are Similar atoms are similar and different atoms are differentdifferent

3.3. Atoms combine to form moleculesAtoms combine to form molecules

4.4. Chemical reactions do not alter atomsChemical reactions do not alter atoms

ElectronsElectrons

J.J. ThomsonJ.J. Thomson

English physicistEnglish physicist Worked on electricity, Worked on electricity,

magnetism, and magnetism, and charged particlescharged particles

Discovered Discovered ELECTRONELECTRON

ElectronsElectrons


Used a cathode ray tube Used a cathode ray tube and experimented with and experimented with the beam of energy.the beam of energy.

Based on deflection with Based on deflection with magnets and electricity, magnets and electricity, he assumed the beam he assumed the beam was made of negative was made of negative particles.particles.

Discovered electronDiscovered electron

ElectronsElectrons


Plum Pudding Model Plum Pudding Model of Atomof Atom

Electrons as discrete Electrons as discrete particlesparticles

Remaining mass an Remaining mass an unorganized glob.unorganized glob.

NucleusNucleus

Ernest RutherfordErnest Rutherford

Used alpha particles Used alpha particles (Helium atoms) fired at a (Helium atoms) fired at a piece of gold foil.piece of gold foil.

Deflections of the Deflections of the particles made him particles made him assume that there was a assume that there was a massive particle at the massive particle at the center of the atom. center of the atom.

Discovered NucleusDiscovered Nucleus

Gold Foil ExperimentGold Foil Experiment

NeutronNeutron

James ChadwickJames Chadwick

Calculated the mass Calculated the mass of similar atoms.of similar atoms.

Recognized isotopes.Recognized isotopes. First to recognize the First to recognize the

extra mass in the extra mass in the nucleus was a neutral nucleus was a neutral particle…Neutronsparticle…Neutrons

Splitting the AtomSplitting the Atom

Lise MeitnerLise Meitner

Calculated the energy Calculated the energy in in ““Binding EnergyBinding Energy”” in in the nucleus.the nucleus.

First to recognize the First to recognize the disintegration of a disintegration of a nucleusnucleus

RadiationRadiation

Andre Becquerel Andre Becquerel Discovered radiationDiscovered radiation

Marie CurieMarie Curie Early research in Early research in

radiation.radiation.

Ions and IsotopesIons and Isotopes

Three particles in the atomThree particles in the atom

ProtonProton NeutronNeutron ElectronElectronChargedCharged NeutralNeutral ChargedCharged

+1 +1 0 0 -1 -1

Has MassHas Mass Has MassHas Mass No MassNo Mass

1 AMU1 AMU 1 AMU 1 AMU 0 AMU 0 AMU

IonsIons

Ions have Three CharacteristicsIons have Three Characteristics

1.1. Ions are charged particlesIons are charged particles

2.2. Protons not equal to electronsProtons not equal to electrons

3.3. Can be positive or negativeCan be positive or negative

IonsIons

Calculate the ChargeCalculate the ChargeA Carbon atom with 6 protons, six neutrons and A Carbon atom with 6 protons, six neutrons and

six electronssix electrons

(6 protons x (+1)) = +6(6 protons x (+1)) = +6(6 neutrons x (0)) = 0(6 neutrons x (0)) = 0

(6 electrons x (-1)) = -6 (6 electrons x (-1)) = -6

Sum = 0 (no charge)Sum = 0 (no charge)

IonsIons

Calculate the ChargeCalculate the ChargeA Carbon atom with 6 protons, six neutrons and A Carbon atom with 6 protons, six neutrons and

four electronsfour electrons

(6 protons x (+1)) = +6(6 protons x (+1)) = +6(6 neutrons x (0)) = 0(6 neutrons x (0)) = 0

(4 electrons x (-1)) = -4 (4 electrons x (-1)) = -4

Charge = +2Charge = +2

IsotopesIsotopes

Isotopes are all about MassIsotopes are all about Mass

Compare protons and neutronsCompare protons and neutrons

If protons and neutrons are If protons and neutrons are NOTNOT equal, then the equal, then the atom is an isotope.atom is an isotope.

IsotopesIsotopes

Calculate the MassCalculate the MassA Carbon atom with 6 protons, 6 neutrons and A Carbon atom with 6 protons, 6 neutrons and

4 electrons4 electrons

(6 protons x (1 AMU)) = 6 AMU(6 protons x (1 AMU)) = 6 AMU(6 neutrons x (1 AMU)) = 6 AMU(6 neutrons x (1 AMU)) = 6 AMU(4 electrons x (0 AMU)) = 0 AMU (4 electrons x (0 AMU)) = 0 AMU

Mass = 12 AMUMass = 12 AMU

Isotope NotationIsotope Notation

NiNi28

60 4+

Mass = Protons + Neutrons

Atomic Number or Number of Protons

Charge

Element


FF9

19 1-

KK19

38 1+

NiNi28

60 4+

NN7

15 3-

AsAs33

68 5+

ArAr18

36


BB512 3-

VV23

46 4+

SiSi14

30 4+

ClCl17

37 1-

CuCu29

59 2+

KrKr36

72

ChemistryChemistry

The MoleThe Mole

MoleMole

The mole is a term to describe quantity.The mole is a term to describe quantity.

1 dozen = 12 things1 dozen = 12 things

1 gross = 12 dozen = 144 things1 gross = 12 dozen = 144 things

1 mole = 602,000,000,000,000,000,000,000 things1 mole = 602,000,000,000,000,000,000,000 things

6.02 x 106.02 x 102323 things things

MoleMole

The mass of one mole of an element is the atomic mass.The mass of one mole of an element is the atomic mass.

1 mole of Carbon = 12 grams1 mole of Carbon = 12 grams

1 mole of Sodium = 23 grams1 mole of Sodium = 23 grams

1 mole of Carbon atoms is 6.02 x 101 mole of Carbon atoms is 6.02 x 102323 atoms atoms

1 mole of Sodium atoms is 6.02 x 101 mole of Sodium atoms is 6.02 x 102323 atoms atoms

One is a measure of One is a measure of ““massmass””

The other is a measure of The other is a measure of ““how manyhow many””

The MoleThe MoleFF

9

19 1-

What is the mass of 2 moles What is the mass of 2 moles of this element?of this element?

How many atoms are present in How many atoms are present in 2 moles of this element?2 moles of this element?

Is this atom an ion an isotope Is this atom an ion an isotope both or neither?both or neither?

Periodic TablePeriodic Table

ObjectivesObjectives Element Names and SymbolsElement Names and Symbols

Periodic Table GeographyPeriodic Table Geography

Characteristics of Major GroupsCharacteristics of Major Groups


Dimitri Mendeleev Dimitri Mendeleev Organized the Organized the

Periodic TablePeriodic Table Made predictions Made predictions

about the elements about the elements yet to be discoveredyet to be discovered


Alkali MetalsAlkali Metals

Alkali MetalsAlkali Metals: Highly reactive : Highly reactive elements that combine with many elements that combine with many nonmetals to form ionic solids (salts). nonmetals to form ionic solids (salts). They also form compounds with They also form compounds with oxygen that dissolve in water to oxygen that dissolve in water to create solutions that are strongly create solutions that are strongly alkaline. alkaline.

Alkaline Earth MetalsAlkaline Earth Metals

Alkaline Earth MetalsAlkaline Earth Metals: Very reactive : Very reactive elements that form ionic compounds elements that form ionic compounds with nonmetals. Many of their oxygen with nonmetals. Many of their oxygen compounds are found in deposits in compounds are found in deposits in the ground.the ground.

Transition MetalsTransition Metals

Transition MetalsTransition Metals: Generally less reactive than the alkali : Generally less reactive than the alkali and alkaline earth metals, these elements vary in physical and alkaline earth metals, these elements vary in physical and chemical properties. Many form important alloys with and chemical properties. Many form important alloys with one another and other metals. Several of the transition one another and other metals. Several of the transition elements can form more than one positive ion. For elements can form more than one positive ion. For example, iron can form more than one ion, Feexample, iron can form more than one ion, Fe 2+ 2+ and Fe and Fe 3+ 3+..

HalogensHalogens

HalogensHalogens: Reactive elements that : Reactive elements that form compounds known as halides. form compounds known as halides. Several halogens including chlorine, Several halogens including chlorine, fluorine and iodine, have important fluorine and iodine, have important applications in everyday life.applications in everyday life.

Noble GasesNoble Gases

Noble GasesNoble Gases: Elements are generally not : Elements are generally not reactive; however, the heavier noble gases reactive; however, the heavier noble gases can react with a few halogens. These can react with a few halogens. These elements have generally complete electron elements have generally complete electron shells. They are gases at very low and very shells. They are gases at very low and very high temperatures.high temperatures.

MetalloidsMetalloids

MetalloidsMetalloids: Elements that : Elements that display characteristics of both display characteristics of both metals and non-metals. They metals and non-metals. They are only partial conductors of are only partial conductors of electricity and are therefore electricity and are therefore also known as semiconductors.also known as semiconductors.

Non-MetalsNon-Metals

Non-MetalsNon-Metals: Elements that do : Elements that do not display characteristics of not display characteristics of metals. They are not shiny, metals. They are not shiny, they do not conduct electricity, they do not conduct electricity, and they are not malleableand they are not malleable

MetalsMetals: Elements that display : Elements that display characteristics of metals. They characteristics of metals. They are shiny, they conduct are shiny, they conduct electricity, and they are electricity, and they are malleablemalleable

Documents

Atomic Theory