Present at a Ion 01

8/14/2019 Present at a Ion 01

http://slidepdf.com/reader/full/present-at-a-ion-01 1/59

Well comeThis PowerPoint presentation hasbeen made by Kabita The group

leader NishaNidhi NehaKavita

Well comeThis PowerPoint presentation hasbeen made by Kabita The group

leader NishaNidhi NehaKavita



Structure of AtomStructure of Atom



• Atoms and molecules are the building

blocks of matter.

• The existence of different kinds of matter

around us is due to different types of atoms

are the smallest particle of an element.• to different types of atoms and molecules

present in them.

• The atoms are divisible and they do have

an inner structure.

• Atoms have smaller particles in them which

are called subatomic particles.

• Atoms and molecules are the building

blocks of matter.

• The existence of different kinds of matter

around us is due to different types of atoms

are the smallest particle of an element.• to different types of atoms and molecules

present in them.

• The atoms are divisible and they do have

an inner structure.

• Atoms have smaller particles in them which

are called subatomic particles.

ATOMATOM



DALTON’S ATOMIC THEORYDALTON’S ATOMIC THEORY

According to “DALTON’S ATOMIC THEORY’’ ,all

matter , whether an element , a compound or amixture is composed of small particles called atoms ,

the postulates of this theory may be stated as

follows:

• All matter is made of very tiny particles called atoms.

• Atoms are indivisible particles , which cannot becreated nor be destroyed in a chemical reaction.

• Atoms of a given element are identical in mass and

chemical reaction.

• Atoms of different elements have different masses

and chemical properties.

• Atoms combine in the ratio of small whole numbers

to form compounds.

• The relative number and kinds of atoms are

Constant in a given compound.

According to “DALTON’S ATOMIC THEORY’’ ,all

matter , whether an element , a compound or amixture is composed of small particles called atoms ,

the postulates of this theory may be stated as

follows:

• All matter is made of very tiny particles called atoms.

• Atoms are indivisible particles , which cannot becreated nor be destroyed in a chemical reaction.

• Atoms of a given element are identical in mass and

chemical reaction.

• Atoms of different elements have different masses

and chemical properties.

• Atoms combine in the ratio of small whole numbers

to form compounds.

• The relative number and kinds of atoms are

Constant in a given compound.



Subatomic ParticlesSubatomic ParticlesSubatomic ParticlesSubatomic Particles

3 types:3 typ

es:

• Electron:Electron: negatively

charged• Proton:Proton: positively

charged

• Neutron:Neutron: neutralparticles

3 typ

es:3 typ

es:

• Electron:Electron: negatively

charged• Proton:Proton: positively

charged

• Neutron:Neutron: neutralparticles



Subatomic ParticlesSubatomic Particles

ParticleParticle ChargeCharge Mass (g)Mass (g) LocationLocation

ElectronElectron

(e(e--)) -1-1 9.11 x 109.11 x 10-28-28 ElectronElectron

cloudcloud

ProtonProton

(p(p++)) +1+1

1010-24-24

1.67 x1.67 x NucleusNucleus

NeutronNeutron

(n(noo)) 00 1.67 x 101.67 x 10-24-24 NucleusNucleus



The number of subatomicparticles in the following:The number of subatomicparticles in the following:

.Cl has a mass # of 35 and an atomic #of 17– p+ = 17, no = 18, e- = 17

• K has a mass # of 39 and an atomic #of 19– P+ = 19, no = 20 e- = 19.

.Cl has a mass # of 35 and an atomic #of 17– p+ = 17, no = 18, e- = 17

• K has a mass # of 39 and an atomic #of 19– P+ = 19, no = 20 e- = 19.



ELECTRONS ELECTRONS ELECTRONS ELECTRONS

• The existence of electrons in anatom was shown by

J.J.Thomson in 1897.

• Thomson was englishphysicsts.

• The existence of electrons in anatom was shown by

J.J.Thomson in 1897.

• Thomson was englishphysicsts.



DISCOVERY OF ELECTRONS DISCOVERY OF ELECTRONS DISCOVERY OF ELECTRONS DISCOVERY OF ELECTRONS

Since all the gases from cathode rays, it wasSince all the gases from cathode rays, it was

concluded that all the atoms containconcluded that all the atoms contain

negatively charged particles called electron.negatively charged particles called electron.

Fast moving electron from cathode rays.Fast moving electron from cathode rays.

The electron is a negatively chargedThe electron is a negatively charged

particles found in the atoms of all theparticles found in the atoms of all the

elements.elements.The electrons are located outside theThe electrons are located outside the

nucleus in an atom.nucleus in an atom.

Cathode rays consists of small, negativelyCathode rays consists of small, negatively

charged particles called electrons .charged particles called electrons .

The existence of electrons in an atom wasThe existence of electrons in an atom wasshown by J.H. Thomson in 1897.shown by J.H. Thomson in 1897.

Since all the gases from cathode rays, it wasSince all the gases from cathode rays, it was

concluded that all the atoms containconcluded that all the atoms contain

negatively charged particles called electron.negatively charged particles called electron.

Fast moving electron from cathode rays.Fast moving electron from cathode rays.

The electron is a negatively chargedThe electron is a negatively charged

particles found in the atoms of all theparticles found in the atoms of all the

elements.elements.The electrons are located outside theThe electrons are located outside the

nucleus in an atom.nucleus in an atom.

Cathode rays consists of small, negativelyCathode rays consists of small, negatively

charged particles called electrons .charged particles called electrons .

The existence of electrons in an atom wasThe existence of electrons in an atom wasshown by J.H. Thomson in 1897.shown by J.H. Thomson in 1897.



DISCOVERY OF PROTONDISCOVERY OF PROTON• Protons are the positively charged

particles the existence of proton in the

atoms was shown by E.Goldstein.• When Goldstein passed electricity at high

voltage through a gas at very low

pressure taken in a discharge tube,

stream of heavy particles were given out

by the anode.• These streams of particles are called

anode rays.

• Anode rays consists of positively charged

particles.

• The anode rays obtained from hydrogen

gas consists of protons.

• These fast moving proton form the anode

rays, The proton is positively charged

particle found in the atoms of all theelements.

• Protons are the positively charged

particles the existence of proton in the

atoms was shown by E.Goldstein.• When Goldstein passed electricity at high

voltage through a gas at very low

pressure taken in a discharge tube,

stream of heavy particles were given out

by the anode.• These streams of particles are called

anode rays.

• Anode rays consists of positively charged

particles.

• The anode rays obtained from hydrogen

gas consists of protons.

• These fast moving proton form the anode

rays, The proton is positively charged

particle found in the atoms of all theelements.



DISCOVERY OF PROTONDISCOVERY OF PROTON



CHARACTERISTICS OF AN

ELECTRON

CHARACTERISTICS OF AN

ELECTRONMass of an electronMass of an electron

• The relative mass of an electron isThe relative mass of an electron is

1/1840u.the absolute mass of an1/1840u.the absolute mass of an

electron iselectron is 9.11 x 109.11 x 10-28-28 gram.gram.

Charge of an electronCharge of an electron

• The absolute charge of an electron is1.67 x 10The absolute charge of an electron is1.67 x 10-19-19

coulomb of negative charge . The relative chargecoulomb of negative charge . The relative chargeof an electron is -1[minus one].of an electron is -1[minus one].

Mass of an electronMass of an electron

• The relative mass of an electron isThe relative mass of an electron is

1/1840u.the absolute mass of an1/1840u.the absolute mass of an

electron iselectron is 9.11 x 109.11 x 10-28-28 gram.gram.

Charge of an electronCharge of an electron

• The absolute charge of an electron is1.67 x 10The absolute charge of an electron is1.67 x 10-19-19

coulomb of negative charge . The relative chargecoulomb of negative charge . The relative chargeof an electron is -1[minus one].of an electron is -1[minus one].



NEUTRONNEUTRON

• Neutron was

discovered by thephysician sir

Chadwick in 1932.

• Neutron was

discovered by thephysician sir

Chadwick in 1932.



DISCOVERY OF NEUTRONDISCOVERY OF NEUTRON

• The Neutron is a neutral particle found in the nucleus of anatom.

• The sub atomic particle not present in hydrogen atom is

neutron.

• The sub atomic particles not present in the hydrogen is neutron.• This problem was solve by the discovery of another sub atomic

particle by Chadwick in 1932.

• The neutron is a neutral particle found in the nucleus of an

atom.• Thus the sub atomic particles not present in a hydrogen atom is

neutron.

• An hydrogen atom contain only one proton and one electron.

• A neutron is represented by the symbol N.

• The Neutron is a neutral particle found in the nucleus of anatom.

• The sub atomic particle not present in hydrogen atom is

neutron.

• The sub atomic particles not present in the hydrogen is neutron.• This problem was solve by the discovery of another sub atomic

particle by Chadwick in 1932.

• The neutron is a neutral particle found in the nucleus of an

atom.• Thus the sub atomic particles not present in a hydrogen atom is

neutron.

• An hydrogen atom contain only one proton and one electron.

• A neutron is represented by the symbol N.





THOMSON’S MODEL OF THE ATOMTHOMSON’S MODEL OF THE ATOMTHOMSON’S MODEL OF THE ATOMTHOMSON’S MODEL OF THE ATOM

When J.J. Thomson proposed his model of When J.J. Thomson proposed his model of thethe

atom in 1930, then only electron andatom in 1930, then only electron andprotonsprotons

known to be present in the atom. Accordingknown to be present in the atom. Accordingtoto

Thomson model of the atom:Thomson model of the atom:

1.1. An atom consists of sphere of positiveAn atom consists of sphere of positivecharged with negatively chargedcharged with negatively chargedelectron embedded in it.electron embedded in it.

2.2. The positive and negative charged inThe positive and negative charged inan atom are equal in magnitude, due toan atom are equal in magnitude, due towhich an atom is electrically neutron itwhich an atom is electrically neutron it

has not overall positive or negativehas not overall positive or negativecharged.charged.

When J.J. Thomson proposed his model of When J.J. Thomson proposed his model of thethe

atom in 1930, then only electron andatom in 1930, then only electron andprotonsprotons

known to be present in the atom. Accordingknown to be present in the atom. Accordingtoto

Thomson model of the atom:Thomson model of the atom:

1.1. An atom consists of sphere of positiveAn atom consists of sphere of positivecharged with negatively chargedcharged with negatively charged

electron embedded in it.electron embedded in it.

2.2. The positive and negative charged inThe positive and negative charged inan atom are equal in magnitude, due toan atom are equal in magnitude, due towhich an atom is electrically neutron itwhich an atom is electrically neutron it

has not overall positive or negativehas not overall positive or negativecharged.charged.



Thomson’s Atomic ModelThomson’s Atomic Model

Thomson believed that

the electrons were like

plums embedded in a

positively charged

“pudding,” thus it was

called the “plum pudding”model.

J. J. ThomsonJ. J. Thomson



Thomson’s Atomic ModelThomson’s Atomic Model





Gold foilGold foil



Gold foilGold foil



Gold foilGold foil



RUTHERFORD’S MODEL OF THERUTHERFORD’S MODEL OF THEATOMATOM


1.1. An atom consists of a positively charged,An atom consists of a positively charged,dense and very small nucleus containing ondense and very small nucleus containing onthe proton and neutron. Almost the entire massthe proton and neutron. Almost the entire massof an atom is concentrated in the nucleus.of an atom is concentrated in the nucleus.

2.2. The nucleus is surrounded by negativelyThe nucleus is surrounded by negativelycharged electrons. The electron are revolvingcharged electrons. The electron are revolvinground the nucleus in circular paths at very highround the nucleus in circular paths at very highspeed. The circular path of the electron arespeed. The circular path of the electron arecalled orbits.called orbits.

3.3. The electrostatic attraction between theThe electrostatic attraction between thepositively charged nucleus and negativelypositively charged nucleus and negatively

charged electron hold the atom together.charged electron hold the atom together.4.4. An atom is electrical neutral. This is becauseAn atom is electrical neutral. This is because

the number of protons an electrons in an atomthe number of protons an electrons in an atomis equal.is equal.

5.5. Most of the atom is empty space.Most of the atom is empty space.

1.1. An atom consists of a positively charged,An atom consists of a positively charged,dense and very small nucleus containing ondense and very small nucleus containing onthe proton and neutron. Almost the entire massthe proton and neutron. Almost the entire massof an atom is concentrated in the nucleus.of an atom is concentrated in the nucleus.

2.2. The nucleus is surrounded by negativelyThe nucleus is surrounded by negativelycharged electrons. The electron are revolvingcharged electrons. The electron are revolvinground the nucleus in circular paths at very highround the nucleus in circular paths at very highspeed. The circular path of the electron arespeed. The circular path of the electron arecalled orbits.called orbits.

3.3. The electrostatic attraction between theThe electrostatic attraction between thepositively charged nucleus and negativelypositively charged nucleus and negatively

charged electron hold the atom together.charged electron hold the atom together.4.4. An atom is electrical neutral. This is becauseAn atom is electrical neutral. This is because

the number of protons an electrons in an atomthe number of protons an electrons in an atomis equal.is equal.

5.5. Most of the atom is empty space.Most of the atom is empty space.









• Based on his experimental evidence:

– The atom is mostly empty space

– All the positive charge, and almost all

the mass is concentrated in a small areain the center. He called this a “nucleus”

– The nucleus is comosed of protons andneutrons (they make the nucleus!)

–The electrons distributed around thenucleus, and occupy most of the volume

– His model was called a “nuclear model”


– The atom is mostly empty space

– All the positive charge, and almost all

the mass is concentrated in a small areain the center. He called this a “nucleus”

– The nucleus is comosed of protons andneutrons (they make the nucleus!)

– The electrons distributed around thenucleus, and occupy most of the volume

– His model was called a “nuclear model”

• RUTHERFORD’S ALPHA PARTICLESSCATTERING EXPERICEMENT SHOWS THE

PRESENTS OF NUCLEUS IN THE ATOM

• RUTHERFORD’S ALPHA PARTICLESSCATTERING EXPERICEMENT SHOWS THE

PRESENTS OF NUCLEUS IN THE ATOM



SCATTERING OF ALPHA PARTICLES BY A GOLD

FOIL

SCATTERING OF ALPHA PARTICLES BY A GOLD

FOIL



Gold foilGold foil



Expectations versus RealityExpectations versus Reality

Ernest Rutherford’sErnest Rutherford’s



Ernest Rutherford s

Gold Foil Experiment - 1911

Ernest Rutherford s

Gold Foil Experiment - 1911



THE ATOM

THE ATOM

A Major draw back of Rutherford’s model of the atom isA Major draw back of Rutherford’s model of the atom is

that he doesn’t explain the stability of the atom.that he doesn’t explain the stability of the atom.

According to the electromagnetic theory of physics, if According to the electromagnetic theory of physics, if

charged particle undergoes accelerated motion then itcharged particle undergoes accelerated motion then it

must radiate energy continuously. Negatively chargedmust radiate energy continuously. Negatively charged

electrons revolving around the nucleus with acceleratedelectrons revolving around the nucleus with acceleratedmotion, will loss the energy continuously by radiation.motion, will loss the energy continuously by radiation.

Thus, the energy of revolving electron will decreasedThus, the energy of revolving electron will decreased

gradually and there speed will also go on decreasing.gradually and there speed will also go on decreasing.

The electrons will then the attracted more strongly by theThe electrons will then the attracted more strongly by theoppositely charged nucleus due to which they will comeoppositely charged nucleus due to which they will come

more and more close to the nucleus. An ultimately themore and more close to the nucleus. An ultimately the

electron should fall into the nucleus by taking a spiralelectron should fall into the nucleus by taking a spiral

part. This should make the atom very unstable and hencepart. This should make the atom very unstable and hence

the atom should collapse.the atom should collapse.

Th R th f d At i M d lTh R th f d At i M d l



The Rutherford Atomic ModelThe Rutherford Atomic Model• Based on his experimental evidence:

–The atom is mostly empty space –All the positive charge, and almost all

the mass is concentrated in a small area

in the center. He called this a “nucleus” –The nucleus is composed of protons

and neutrons (they make the nucleus!)


–His model was called a “nuclear model”








Th R th f d At i M d lTh R th f d At i M d l



The Rutherford Atomic ModelThe Rutherford Atomic Model• Based on his experimental evidence:
















Rutherford’s problem:Rutherford’s problem:In the following pictures, there is a targetIn the following pictures, there is a target

hidden by a cloud. To figure out the shape of hidden by a cloud. To figure out the shape of the target, we shot some beams into the cloudthe target, we shot some beams into the cloud

and recorded where the beams came out. Canand recorded where the beams came out. Can

you figure out the shape of the target?you figure out the shape of the target?

TargetTarget

#1#1

TargetTarget

#2#2



The Answers:The Answers:

Target #1Target #1 Target #2Target #2

NEILS BOHR MODEL OF THE ATOMNEILS BOHR MODEL OF THE ATOM



NEILS BOHR MODEL OF THE ATOMNEILS BOHR MODEL OF THE ATOM

1. An atom is made of three particles: Electrons, Protons andNeutrons.

Due to the presences of equal number of negative electrons andpositive protons the atom on the hold is electrically neutral.

2. The proton and neutron are located in a small nucleus at the center of the atom. Due to the presences of proton, Nucleus is positively

charged.3. The electron revolved round the nucleus in a fix circular paths

called energy level or shells.

4. The energy level are represented by the number 1,2,3,4,5 and 6 bythe later K,L,M,O.

5. There is a limit to the number of electron which is energy level canhold for example the first energy level K. Shell can hold amaximum of two electron second level can hold a eight electron.The third energy level can hold 18 electron and forth energy levelcan hold 32 electron.

1. An atom is made of three particles: Electrons, Protons andNeutrons.

Due to the presences of equal number of negative electrons andpositive protons the atom on the hold is electrically neutral.

2. The proton and neutron are located in a small nucleus at the center of the atom. Due to the presences of proton, Nucleus is positively

charged.3. The electron revolved round the nucleus in a fix circular pathscalled energy level or shells.

4. The energy level are represented by the number 1,2,3,4,5 and 6 bythe later K,L,M,O.

5. There is a limit to the number of electron which is energy level canhold for example the first energy level K. Shell can hold amaximum of two electron second level can hold a eight electron.The third energy level can hold 18 electron and forth energy levelcan hold 32 electron.



How exactly are the particles

arranged?

How exactly are the particles

arranged?

• Bohr Model of the atom:Reviewers think this could lead to misconceptions!

• Bohr Model of the atom:Reviewers think this could lead to misconceptions!

All of theAll of theprotonsprotons

and theand theneutronsneutrons

The 1The 1stst ringringcan hold upcan hold up

to 2 eto 2 e--

The 2The 2ndnd ringringcan hold upcan hold up

to 8 eto 8 e--

The 3The 3rdrd ring canring canhold uphold up

to 18 eto 18 e--

The 4The 4thth ring andring andany after canany after canhold up to 32 ehold up to 32 e--

ATOMIC NUMBERATOMIC NUMBER



ATOMIC NUMBERATOMIC NUMBER

The number of proton in one atom of an elementis known as atomic number of the element.

Atomic number of an element = Number of proton

in one element of an atom.The atomic number is denoted by later Z. All the

atom of the same element have the same

number of proton in the nuclei, and hence they have the

same atomic number.

The atomic number of an element = Number of

The number of proton in one atom of an elementis known as atomic number of the element.

Atomic number of an element = Number of proton

in one element of an atom.The atomic number is denoted by later Z. All the

atom of the same element have the same

number of proton in the nuclei, and hence they have the

same atomic number.

The atomic number of an element = Number of



Atomic Number Atomic Number

Atomic number (Z) of an element isAtomic number (Z) of an element is

the number of protons in the nucleusthe number of protons in the nucleus

of each atom of that element.of each atom of that element.

ElementElement # of protons# of protons Atomic # (Z)Atomic # (Z)

CarbonCarbon 66 66

PhosphorusPhosphorus 1515 1515

GoldGold 7979 7979



Atomic Number Atomic Number

•Atoms are composed of

identical protons, neutrons, and electrons

– How then are atoms of one element

different from another element?• Elements are different because they

contain different numbers of PROTONS

• The “atomic number ” of an element isthe number of protons in the nucleus

• # protons in an atom = # electrons

• Atoms are composed of identical

protons, neutrons, and electrons

– How then are atoms of one element

different from another element?• Elements are different because they

contain different numbers of PROTONS

• The “atomic number ” of an element isthe number of protons in the nucleus

• # protons in an atom = # electrons



Atomic MassAtomic Mass

Total number of proton and neutron present in

one atom of an element is known as its mass

number.

Mass number = Number of proton + Number of Neutron.

The mass number of an element is denoted by

latter A. Mass number = atomic mass

Total number of proton and neutron present in

one atom of an element is known as its mass

number.

Mass number = Number of proton + Number of Neutron.

The mass number of an element is denoted by

latter A. Mass number = atomic mass

Atomic MassesAtomic Masses



Atomic MassesAtomic Masses

IsotopeIsotope SymbolSymbol Composition of Composition of the nucleusthe nucleus

% in nature% in nature

Carbon-12Carbon-12 1212 CC 6 protons6 protons

6 neutrons6 neutrons

98.89%98.89%

Carbon-13Carbon-13 1313 CC 6 protons6 protons

7 neutrons7 neutrons

1.11%1.11%

Carbon-14Carbon-14 1414 CC 6 protons6 protons8 neutrons8 neutrons

<0.01%<0.01%

Atomic mass is the average of all theAtomic mass is the average of all the

naturally occurring isotopes of thatnaturally occurring isotopes of that

element.element.

Carbon = 12.011Carbon = 12.011



• Mass number: the number of protons

and neutrons in the nucleus– Ex: hydrogen can have a mass of 3.

Since it has 1 proton it must have 2

neutrons

– # of neutrons = mass # - atomic #

• Mass number: the number of protons

and neutrons in the nucleus– Ex: hydrogen can have a mass of 3.

Since it has 1 proton it must have 2

neutrons

– # of neutrons = mass # - atomic #

How do we know the number of

subatomic particles in an atom?

How do we know the number of

subatomic particles in an atom?



Measuring Atomic MassMeasuring Atomic Mass

• Instead of grams, the unit we useis the Atomic Mass Unit (amu)

• It is defined as one-twelfth themass of a carbon-12 atom. – Carbon-12 chosen because of its isotope purity.

• Each isotope has its own atomicmass, thus we determine theaverage from percent abundance.

• Instead of grams, the unit we useis the Atomic Mass Unit (amu)

• It is defined as one-twelfth themass of a carbon-12 atom. – Carbon-12 chosen because of its isotope purity.

• Each isotope has its own atomicmass, thus we determine theaverage from percent abundance.

Mass NumberMass Number



Mass Number Mass Number

Mass number is the number of protonsMass number is the number of protons

and neutrons in the nucleus of anand neutrons in the nucleus of an

isotope:isotope: Mass # = pMass # = p++ + n+ n00

NuclideNuclide pp++ nn00 ee-- Mass #Mass #

OxygenOxygen -- 1010

-- 3333 4242

-- 3131 1515

88 88 18181818

ArsenicArsenic 7575 3333 7575

PhosphorusPhosphorus 1515 31311616



Complete SymbolsComplete Symbols

• Contain the symbol of the element,the mass number and the atomic

number.

• Contain the symbol of the element,the mass number and the atomic

number.

XX

MassMassnumber number

AtomicAtomic

number number SubscriptSubscript →→

Superscript →Superscript →



SymbolsSymbols

s Find each of these:Find each of these:a)a) number of protonsnumber of protons

b)b) number of number of neutronsneutrons

c)c) number of number of

electronselectronsd)d) Atomic number Atomic number

e)e) Mass Number Mass Number

Br Br 8080

3535



SymbolsSymbols

s If an element has an atomicIf an element has an atomicnumber of 34 and a massnumber of 34 and a mass

number of 78, what is the:number of 78, what is the:

a)a) number of protonsnumber of protons

b)b) number of neutronsnumber of neutrons

c)c) number of electronsnumber of electrons

d)d) complete symbolcomplete symbol



IsotopesIsotopes

• Dalton was wrong about allelements of the same typebeing identical

• Atoms of the same element can have different numbers of

neutrons.• Thus, different mass numbers.

• These are called isotopes.

• Dalton was wrong about allelements of the same typebeing identical

• Atoms of the same element can have different numbers of

neutrons.• Thus, different mass numbers.

• These are called isotopes.



IsotopesIsotopes

• Frederick Soddy (1877-1956)

proposed the idea of isotopes in 1912

• Isotopes are atoms of the same elementhaving different masses, due to varying

numbers of neutrons.

• Soddy won the Nobel Prize in Chemistry in

1921 for his work with isotopes and

radioactive materials.

• Frederick Soddy (1877-1956)

proposed the idea of isotopes in 1912

• Isotopes are atoms of the same element having different masses, due to varying

numbers of neutrons.

• Soddy won the Nobel Prize in Chemistry in

1921 for his work with isotopes and

radioactive materials.



Naming IsotopesNaming Isotopes

• We can also put the massnumber after the name of the

element: –carbon-12

–carbon-14 –uranium-235

• We can also put the massnumber after the name of the

element: –carbon-12

–carbon-14 –uranium-235

I tI t t f tht f th l tl t h ih i



IsotopesIsotopes are atoms of theare atoms of the same elementsame element havinghaving

different massesdifferent masses, due to varying numbers of , due to varying numbers of

neutrons.neutrons.IsotopeIsotope ProtonsProtons ElectronsElectrons NeutronsNeutrons NucleusNucleus

Hydrogen–1Hydrogen–1

(protium)(protium) 11 11 00

Hydrogen-2Hydrogen-2

(deuterium)(deuterium) 11 11 11

Hydrogen-3Hydrogen-3(tritium)(tritium)

11 11 22

II t



IsotopesIsotopesElementsElements

occur inoccur innature asnature as

mixturesmixtures of of

isotopes.isotopes.

Isotopes areIsotopes are

atoms of theatoms of the

same elementsame elementthat differ inthat differ in

thethe number of number of

neutrons.neutrons.



1922 Niels Bohr 1922 Niels Bohr

• Electrons closer to the nucleus have lower energy and are more stable due to strong

electrostatic attraction with the nucleus.

• The letter “n” is used to designate energy

levels (orbits), with lower whole number values of n representing lower energy orbits

closer to the nucleus.

• The key to Bohr’s Quantum Model was that

electrons are restricted to certain“allowed” energy levels in atoms.

• Whereas Rutherford suggested electrons

orbit the nucleus, Bohr’s model required that

they occupy only certain orbits!

• Electrons closer to the nucleus have lower energy and are more stable due to strong

electrostatic attraction with the nucleus.

• The letter “n” is used to designate energy

levels (orbits), with lower whole number values of n representing lower energy orbits

closer to the nucleus.

• The key to Bohr’s Quantum Model was that

electrons are restricted to certain“allowed” energy levels in atoms.

• Whereas Rutherford suggested electrons

orbit the nucleus, Bohr’s model required that

they occupy only certain orbits!



Representative, Transition, & Rare Earth

Elements

Representative, Transition, & Rare Earth

Elements





Cathode Ray TubesCathode Ray Tubes



2



Thank

You

Thank

You• For your cooperation with us during

our presentation we hope that it

helps you in giving some kind of

information on the topic thestructure of the atom

• For your cooperation with us duringour presentation we hope that it

helps you in giving some kind of

information on the topic thestructure of the atom

Documents

Present at a Ion 01