Download View PDF

THE STRUCTURE
OF THE ATOM
ATOMIC MODELS
Tuesday, October 8, 13
PIONEERS OF THE ATOM
Tuesday, October 8, 13
PIONEERS OF THE ATOM
• DEMOCRITUS
Tuesday, October 8, 13
PIONEERS OF THE ATOM
• DEMOCRITUS
• LAVOISIER
Tuesday, October 8, 13
PIONEERS OF THE ATOM
• DEMOCRITUS
• LAVOISIER
• DALTON
Tuesday, October 8, 13
PIONEERS OF THE ATOM
•
•
•
•
DEMOCRITUS
LAVOISIER
DALTON
THOMPSON
Tuesday, October 8, 13
PIONEERS OF THE ATOM
•
•
•
•
DEMOCRITUS
LAVOISIER
DALTON
THOMPSON
• MILLIKEN
Tuesday, October 8, 13
PIONEERS OF THE ATOM
•
•
•
•
DEMOCRITUS
LAVOISIER
DALTON
THOMPSON
• MILLIKEN
• RUTHERFORD
Tuesday, October 8, 13
THE EARLY ATOM
• DEMOCRITUS IS
THE MAN!!!
• YOU KNOW IT!
Tuesday, October 8, 13
THE EARLY ATOM
IT’S ALL
GREEK
TO ME...
• DEMOCRITUS IS
THE MAN!!!
• YOU KNOW IT!
Tuesday, October 8, 13
DEMOCRITUS
Tuesday, October 8, 13
DEMOCRITUS
• WAS A GREEK PHILOSOPHER THAT
BEGAN WONDERING WHAT WAS THE
UNIVERSE MADE UP OF.
Tuesday, October 8, 13
DEMOCRITUS
• WAS A GREEK PHILOSOPHER THAT
BEGAN WONDERING WHAT WAS THE
UNIVERSE MADE UP OF.
• HE PROPOSED THAT ALL THE
MATTER IN THE UNIVERSE IS
COMPOSED OF TINY PARTICLES
Tuesday, October 8, 13
DEMOCRITUS
• WAS A GREEK PHILOSOPHER THAT
BEGAN WONDERING WHAT WAS THE
UNIVERSE MADE UP OF.
• HE PROPOSED THAT ALL THE
MATTER IN THE UNIVERSE IS
COMPOSED OF TINY PARTICLES
• THESE PARTICLES ARE INDIVISABLE
Tuesday, October 8, 13
DEMOCRITUS
• WAS A GREEK PHILOSOPHER THAT
BEGAN WONDERING WHAT WAS THE
UNIVERSE MADE UP OF.
• HE PROPOSED THAT ALL THE
MATTER IN THE UNIVERSE IS
COMPOSED OF TINY PARTICLES
• THESE PARTICLES ARE INDIVISABLE
• HE CALLED THESE PARTICLES
ATOMOS (MEANS INDIVISABLE)
Tuesday, October 8, 13
DEMOCRITUS
• WAS A GREEK PHILOSOPHER THAT
BEGAN WONDERING WHAT WAS THE
UNIVERSE MADE UP OF.
• HE PROPOSED THAT ALL THE
MATTER IN THE UNIVERSE IS
COMPOSED OF TINY PARTICLES
• THESE PARTICLES ARE INDIVISABLE
• HE CALLED THESE PARTICLES
ATOMOS (MEANS INDIVISABLE)
• BUT HE HAD AN OPPONENT…
Tuesday, October 8, 13
Tuesday, October 8, 13
ARISTOTLE = SCEPTIC
DEMOCRITUS IS
AN
IGNORAMUS!
Tuesday, October 8, 13
ARISTOTLE = SCEPTIC
DEMOCRITUS IS
AN
IGNORAMUS!
ARISTOTLE WAS
MUCH MORE
POPULAR AND HE
OPPOSED THE IDEA
OF ATOMS!
Tuesday, October 8, 13
ARISTOTLE = SCEPTIC
DEMOCRITUS IS
AN
IGNORAMUS!
ARISTOTLE BELIEVED
THAT MATTER WAS
CONTINUOUS.
Tuesday, October 8, 13
DEMOCRITUS’
ATOMS
Tuesday, October 8, 13
DEMOCRITUS’
ATOMS
Tuesday, October 8, 13
SO...CHEMISTRY DIED
FOR ABOUT 1400 YEARS
Tuesday, October 8, 13
SO...CHEMISTRY DIED
FOR ABOUT 1400 YEARS
UNTIL...
Tuesday, October 8, 13
SO...CHEMISTRY DIED
FOR ABOUT 1400 YEARS
IN THE
1700’S
Tuesday, October 8, 13
FOUNDATIONS OF
ATOMIC THEORY
Tuesday, October 8, 13
FOUNDATIONS OF
ATOMIC THEORY
• THE PREDOMINATE BELIEF BY THE
MID 1700’S WAS THE MODERN
DEFINITION OF AN ELEMENT AS A
SUBSTANCE THAT CANNOT BE
BROKEN DOWN BY ORDINARY
CHEMICAL MEANS
Tuesday, October 8, 13
FOUNDATIONS OF
ATOMIC THEORY
• THE PREDOMINATE BELIEF BY THE
MID 1700’S WAS THE MODERN
DEFINITION OF AN ELEMENT AS A
SUBSTANCE THAT CANNOT BE
BROKEN DOWN BY ORDINARY
CHEMICAL MEANS
• IT WAS ALSO BELIEVED THAT
ELEMENTS COMBINE TO FORM
COMPOUNDS THAT HAVE
DIFFERENT PHYS AND CHEM
PROPERTIES THAN THOSE OF THE
ELEMENTS THAT FORM THEM.
Tuesday, October 8, 13
FOUNDATIONS OF
ATOMIC THEORY
Tuesday, October 8, 13
FOUNDATIONS OF
ATOMIC THEORY
• HOWEVER, THERE WAS
CONTROVERSY AS TO WHETHER
ELEMENTS ALWAYS COMBINE IN
THE SAME RATIO WHEN FORMING A
PARTICULAR COMPOUND.
Tuesday, October 8, 13
FOUNDATIONS OF
ATOMIC THEORY
• HOWEVER, THERE WAS
CONTROVERSY AS TO WHETHER
ELEMENTS ALWAYS COMBINE IN
THE SAME RATIO WHEN FORMING A
PARTICULAR COMPOUND.
• IN THE 1790’S, THE STUDY OF
MATTER WAS REVOLUTIONIZED BY
A NEW EMPHASIS ON THE
QUANTITATIVE ANALYSIS
Tuesday, October 8, 13
FOUNDATIONS OF
ATOMIC THEORY
• HOWEVER, THERE WAS
CONTROVERSY AS TO WHETHER
ELEMENTS ALWAYS COMBINE IN
THE SAME RATIO WHEN FORMING A
PARTICULAR COMPOUND.
• IN THE 1790’S, THE STUDY OF
MATTER WAS REVOLUTIONIZED BY
A NEW EMPHASIS ON THE
QUANTITATIVE ANALYSIS
– SCIENTISTS’ INVESTIGATIONS WERE
MADE MORE ACCURATE BY NEW
IMPROVED BALANCES
Tuesday, October 8, 13
ANTOINNE LAVOISIER TOOK
ADVANTAGE…
MATTER CAN BE
NEITHER CREATED
NOR DESTROYED.
HE BEGAN TO GATHER
EVIDENCE ABOUT HOW
MATTER BEHAVED
BEFORE AND AFTER A
REACTION.
Tuesday, October 8, 13
ANTOINNE LAVOISIER TOOK
ADVANTAGE…
MATTER CAN BE
NEITHER CREATED
NOR DESTROYED.
HE DISCOVERED THAT THE
TOTAL MASS OF THE
INGREDIENTS OF A
CHEMICAL REACTION WAS
THE SAME AS THE TOTAL
MASS OF THE RESULTS
Tuesday, October 8, 13
2 OTHER FUNDAMENTAL IDEAS
WERE INVESTIGATED...
THE LAW OF
DEFINITE
PROPORTION
Tuesday, October 8, 13
2 OTHER FUNDAMENTAL IDEAS
WERE INVESTIGATED...
THE LAW OF
MULTIPLE
PROPORTIONS
Tuesday, October 8, 13
2 OTHER FUNDAMENTAL IDEAS
WERE INVESTIGATED...
I’M BETTER
LOOKING
THAN PROUST!
Tuesday, October 8, 13
LAW OF
DEFINITE
PROPORTIONS
LAW OF
MULTIPLE
PROPORTIONS
A CHEM COMPD IS ALWAYS
COMPOSED OF THE SAME ELEM.
IN THE SAME PROPOR. BY MASS
C
=
O
CO
IF 2 DIFFERENT COMPDS
ARE COMPOSED OF THE
SAME 2 ELEMTS, THEN THE
RATIO OF OF THE ELEMNTS
IS ALWAYS A RATIO OF
=
CARBON
SMALL
WHOLE #’S+
MONOXIDE
CARBON
DIOXIDE
Tuesday, October 8, 13
+
CARBON
MONOXIDE
C
+
+
C
O
O
CO
=
O
CO2
DALTON’S THOUGHTS
Tuesday, October 8, 13
DALTON’S THOUGHTS
• IN 1808, JOHN DALTON PROPOSED
AN EXPLANATION FOR THE LAW OF
CONS OF MASS, THE LAW OF
DEFINITE PROPORTIONS, &
FORMULATED THE LAW OF
MULTIPLE PROPORTIONS.
Tuesday, October 8, 13
DALTON’S THOUGHTS
• IN 1808, JOHN DALTON PROPOSED
AN EXPLANATION FOR THE LAW OF
CONS OF MASS, THE LAW OF
DEFINITE PROPORTIONS, &
FORMULATED THE LAW OF
MULTIPLE PROPORTIONS.
• HE REASONED THAT ELEMENTS
WERE COMPOSED OF ATOMS &
THAT ONLY WHOLE #’S OF ATOMS
CAN COMBINE TO FORM COMPNDS
Tuesday, October 8, 13
DALTON’S THOUGHTS
• IN 1808, JOHN DALTON PROPOSED
AN EXPLANATION FOR THE LAW OF
CONS OF MASS, THE LAW OF
DEFINITE PROPORTIONS, &
FORMULATED THE LAW OF
MULTIPLE PROPORTIONS.
• HE REASONED THAT ELEMENTS
WERE COMPOSED OF ATOMS &
THAT ONLY WHOLE #’S OF ATOMS
CAN COMBINE TO FORM COMPNDS
• HIS IDEAS ARE NOW CALLED THE
ATOMIC THEORY OF MATTER AND
CAN BE SUMMARIZED AS:
Tuesday, October 8, 13
1. ALL MATTER IS COMPOSED
OF EXTREMELY SMALL
PARTICLES CALLED ATOMS
2.
ATOMS OF A GIVEN
ELEMENT ARE IDENTICAL
IN SIZE, MASS, AND OTHER
PROPERTIES; ATOMS OF
DIFFERENT ELEMENTS
DIFFER IN SIZE, MASS, &
OTHER PROPERTIES
Tuesday, October 8, 13
ELEMENT
1
ELEMENT
2
ELEMENT
3
ELEMENT
4
3. ATOMS CANNOT BE
SUBDIVIDED,
CREATED, OR
DESTROYED
4. ATOMS OF DIFFERENT
ELEMENTS COMBINE IN
SIMPLE WHOLE #
RATIOS TO FORM
CHEM COMPDS
5.IN CHEMICAL RXNS,
ATOMS ARE
COMBINED,
SEPARATED, OR
REARRANGED
Tuesday, October 8, 13
+
+
3. ATOMS CANNOT BE
SUBDIVIDED,
CREATED, OR
DESTROYED
4. ATOMS OF DIFFERENT
ELEMENTS COMBINE IN
SIMPLE WHOLE #
RATIOS TO FORM
CHEM COMPDS
5.IN CHEMICAL RXNS,
ATOMS ARE
COMBINED,
SEPARATED, OR
REARRANGED
Tuesday, October 8, 13
+
+
DALTON AND HIS
CONTEMPORARIES
Tuesday, October 8, 13
DALTON AND HIS
CONTEMPORARIES
THE EARLIEST THEORISTS
THOUGHT THE ATOM WAS
HARD AND ROUND,
MUCH LIKE TINY MARBLES
OR BALL BEARINGS.
Tuesday, October 8, 13
STRUCTURE OF THE ATOM
Tuesday, October 8, 13
STRUCTURE OF THE ATOM
• ALTHOUGH DALTON THOUGHT
ATOMS WERE INDIVISIBLE,
INVESTIGATORS IN THE LATE
1800’S PROVED OTHERWISE
Tuesday, October 8, 13
STRUCTURE OF THE ATOM
• ALTHOUGH DALTON THOUGHT
ATOMS WERE INDIVISIBLE,
INVESTIGATORS IN THE LATE
1800’S PROVED OTHERWISE
• IT SOON BECAME CLEAR THAT
ATOMS ARE ACTUALLY COMPOSED
OF SEVERAL BASIC TYPES OF
SMALLER PARTICLES
Tuesday, October 8, 13
STRUCTURE OF THE ATOM
• ALTHOUGH DALTON THOUGHT
ATOMS WERE INDIVISIBLE,
INVESTIGATORS IN THE LATE
1800’S PROVED OTHERWISE
• IT SOON BECAME CLEAR THAT
ATOMS ARE ACTUALLY COMPOSED
OF SEVERAL BASIC TYPES OF
SMALLER PARTICLES
• AND IT’S THE NUMBERS AND
ARRANGEMENTS OF THESE SUBATOMIC PARTICLES THAT
DETERMINES THE IDENTITY OF THE
ATOM.
Tuesday, October 8, 13
STRUCTURE OF THE ATOM
Tuesday, October 8, 13
STRUCTURE OF THE ATOM
• THE FIRST DISCOVERY OF A
SUBATOMIC PARTICLE RESULTED
FROM THE INVESTIGATIONS INTO
THE RELATIONSHIP BETWEEN
ELECTRICITY AND MATTER.
Tuesday, October 8, 13
STRUCTURE OF THE ATOM
• THE FIRST DISCOVERY OF A
SUBATOMIC PARTICLE RESULTED
FROM THE INVESTIGATIONS INTO
THE RELATIONSHIP BETWEEN
ELECTRICITY AND MATTER.
• IN THE LATE 1800’S, MANY
EXPERIMENTS WERE PERFORMED IN
WHICH ELECTRIC CURRENT WAS
PASSED THROUGH VARIOUS GASES
AT LOW PRESS
Tuesday, October 8, 13
STRUCTURE OF THE ATOM
• THE FIRST DISCOVERY OF A
SUBATOMIC PARTICLE RESULTED
FROM THE INVESTIGATIONS INTO
THE RELATIONSHIP BETWEEN
ELECTRICITY AND MATTER.
• IN THE LATE 1800’S, MANY
EXPERIMENTS WERE PERFORMED IN
WHICH ELECTRIC CURRENT WAS
PASSED THROUGH VARIOUS GASES
AT LOW PRESS
– CARRIED OUT IN
TUBES CALLED
CATHODE-RAY TUBES
Tuesday, October 8, 13
STRUCTURE OF THE ATOM
CATHODE RAY TUBE
Tuesday, October 8, 13
STRUCTURE OF THE ATOM
• INVESTIGATORS NOTICED THAT
WHEN CURRENT WAS PASSED
THROUGH A CATHODE RAY TUBE,
THE SURFACE OF THE TUBE
DIRECTLY OPPOSITE THE CATHODE
GLOWED.
CATHODE RAY TUBE
Tuesday, October 8, 13
STRUCTURE OF THE ATOM
CATHODE RAY
CATHODE RAY TUBE
Tuesday, October 8, 13
STRUCTURE OF THE ATOM
• THEY HYPOTHESIZED THAT THE
GLOW WAS CAUSED BY A STREAM
OF PARTICLES
CATHODE RAY
CATHODE RAY TUBE
Tuesday, October 8, 13
STRUCTURE OF THE ATOM
• THEY HYPOTHESIZED THAT THE
GLOW WAS CAUSED BY A STREAM
OF PARTICLES
– THEY CALLED THE STREAM A
CATHODE RAY
CATHODE RAY
CATHODE RAY TUBE
Tuesday, October 8, 13
STRUCTURE OF THE ATOM
CATHODE RAY
CATHODE
ANODE
CATHODE RAY TUBE
Tuesday, October 8, 13
STRUCTURE OF THE ATOM
• THE CATHODE RAY TRAVELED
FROM THE CATHODE TO THE
ANODE WHEN CURRENT WAS
PASSED THROUGH THE TUBE.
CATHODE RAY
CATHODE
ANODE
CATHODE RAY TUBE
Tuesday, October 8, 13
STRUCTURE OF THE ATOM
• THE CATHODE RAY TRAVELED
FROM THE CATHODE TO THE
ANODE WHEN CURRENT WAS
PASSED THROUGH THE TUBE.
• THE CATHODE RAY TUBE OPENED
THE DOOR FOR J.J. THOMPSON
CATHODE RAY
CATHODE
ANODE
CATHODE RAY TUBE
Tuesday, October 8, 13
J. J. THOMPSON
Tuesday, October 8, 13
J. J. THOMPSON
I PLAY WITH
ELECTRONS
Tuesday, October 8, 13
J. J. THOMPSON
Tuesday, October 8, 13
J. J. THOMPSON
• THOMPSON’S INVESTIGATIONS
SUPPLIED EVIDENCE THAT THE
CATHODE RAY COULD BE
DEFLECTED BY APPLYING A
POSITIVELY CHARGED ELECTRIC
FIELD
Tuesday, October 8, 13
J. J. THOMPSON
• THOMPSON’S INVESTIGATIONS
SUPPLIED EVIDENCE THAT THE
CATHODE RAY COULD BE
DEFLECTED BY APPLYING A
POSITIVELY CHARGED ELECTRIC
FIELD
– THIS HELPED
THOMPSON DISCOVER THAT THE
CATHODE RAY WAS
NEGATIVELY
CHARGED.
Tuesday, October 8, 13
Tuesday, October 8, 13
Tuesday, October 8, 13
• THOMPSON WAS ABLE TO MEASURE
THE RATIO OF THE CHARGE OF
CATHODE RAY PARTICLES TO THEIR
MASS
Tuesday, October 8, 13
• THOMPSON WAS ABLE TO MEASURE
THE RATIO OF THE CHARGE OF
CATHODE RAY PARTICLES TO THEIR
MASS
– HE FOUND THAT THE RATIO WAS
THE SAME REGARDLESS OF THE
METAL USED AS THE CATHODE
Tuesday, October 8, 13
• THOMPSON WAS ABLE TO MEASURE
THE RATIO OF THE CHARGE OF
CATHODE RAY PARTICLES TO THEIR
MASS
– HE FOUND THAT THE RATIO WAS
THE SAME REGARDLESS OF THE
METAL USED AS THE CATHODE
• THOMPSON CONCLUDED THAT ALL
CATHODE RAYS ARE COMPOSED OF
IDENTICAL NEGATIVELY CHARGED
PARTICLES
Tuesday, October 8, 13
• THOMPSON WAS ABLE TO MEASURE
THE RATIO OF THE CHARGE OF
CATHODE RAY PARTICLES TO THEIR
MASS
– HE FOUND THAT THE RATIO WAS
THE SAME REGARDLESS OF THE
METAL USED AS THE CATHODE
• THOMPSON CONCLUDED THAT ALL
CATHODE RAYS ARE COMPOSED OF
IDENTICAL NEGATIVELY CHARGED
PARTICLES
– WHICH WERE LATER CALLED
ELECTRONS
Tuesday, October 8, 13
THOMPSON’S ATOMIC MODEL
Tuesday, October 8, 13
THOMPSON’S ATOMIC MODEL
• HE PROPOSED THAT THE ATOM
LOOKS SOMETHING LIKE A
CHOCOLATE CHIP COOKIE
Tuesday, October 8, 13
THOMPSON’S ATOMIC MODEL
• HE PROPOSED THAT THE ATOM
LOOKS SOMETHING LIKE A
CHOCOLATE CHIP COOKIE
THE CHIPS WOULD BE
HIS ELECTRONS
Tuesday, October 8, 13
THOMPSON’S ATOMIC MODEL
• HE PROPOSED THAT THE ATOM
LOOKS SOMETHING LIKE A
CHOCOLATE CHIP COOKIE
THE CHIPS WOULD BE
HIS ELECTRONS
THE COOKIE PART
IS POS. MATTER TO
CANCEL OUT THE NEG.
ELECTRONS
Tuesday, October 8, 13
Tuesday, October 8, 13
• THOMPSON’S EXPERIMENTS
REVEALED THAT THE ELECTRON
HAS A VERY LARGE CHARGE IN
RELATION TO ITS MASS
Tuesday, October 8, 13
• THOMPSON’S EXPERIMENTS
REVEALED THAT THE ELECTRON
HAS A VERY LARGE CHARGE IN
RELATION TO ITS MASS
• IN 1909, ROBERT MILLIKAN,
PERFORMED AN INGENIOUS
EXPERIMENT TO CALCULATE THE
MASS OF AN ELECTRON
Tuesday, October 8, 13
• THOMPSON’S EXPERIMENTS
REVEALED THAT THE ELECTRON
HAS A VERY LARGE CHARGE IN
RELATION TO ITS MASS
• IN 1909, ROBERT MILLIKAN,
PERFORMED AN INGENIOUS
EXPERIMENT TO CALCULATE THE
MASS OF AN ELECTRON
– HE DISCOVERED THAT THE MASS OF
THE ELECTRON IS ABOUT 1/2000TH
THE MASS OF THE SIMPLEST ATOM
(HYDRO.)
Tuesday, October 8, 13
HELLO, MILLIKAN
Tuesday, October 8, 13
HELLO, MILLIKAN
DAT’S RIGHT!
I SAVED THE
DAY!
Tuesday, October 8, 13
Tuesday, October 8, 13
• HIS OIL DROP EXPERIMENT SHOWED
THAT EVEN THOUGH THE ATOMS
OF DIFFERENT ELEMENTS ARE VERY
DIFFERENT, THEIR ELECTRONS ARE
IDENTICAL.
Tuesday, October 8, 13
• HIS OIL DROP EXPERIMENT SHOWED
THAT EVEN THOUGH THE ATOMS
OF DIFFERENT ELEMENTS ARE VERY
DIFFERENT, THEIR ELECTRONS ARE
IDENTICAL.
– AN ELECTRON IS AN ELECTRON
Tuesday, October 8, 13
• HIS OIL DROP EXPERIMENT SHOWED
THAT EVEN THOUGH THE ATOMS
OF DIFFERENT ELEMENTS ARE VERY
DIFFERENT, THEIR ELECTRONS ARE
IDENTICAL.
– AN ELECTRON IS AN ELECTRON
– THE DIFFERENCE BETWEEN TWO
DIFFERENT ATOMS IS THEIR NUMBER
OF ELECTRONS NOT THEIR TYPE OF
ELECTRON.
Tuesday, October 8, 13
• HIS OIL DROP EXPERIMENT SHOWED
THAT EVEN THOUGH THE ATOMS
OF DIFFERENT ELEMENTS ARE VERY
DIFFERENT, THEIR ELECTRONS ARE
IDENTICAL.
– AN ELECTRON IS AN ELECTRON
– THE DIFFERENCE BETWEEN TWO
DIFFERENT ATOMS IS THEIR NUMBER
OF ELECTRONS NOT THEIR TYPE OF
ELECTRON.
• HE ALSO CALCULATED THAT THE
ELECTRON’S MASS IS 9.109x10-31kg
Tuesday, October 8, 13
SO FAR WE’VE LEARNED…
Tuesday, October 8, 13
SO FAR WE’VE LEARNED…
• THOMPSON’S & MILLIKAN’S IDEAS:
Tuesday, October 8, 13
SO FAR WE’VE LEARNED…
• THOMPSON’S & MILLIKAN’S IDEAS:
– ATOMS ARE IN FACT DIVISABLE
Tuesday, October 8, 13
SO FAR WE’VE LEARNED…
• THOMPSON’S & MILLIKAN’S IDEAS:
– ATOMS ARE IN FACT DIVISABLE
– ELECTRONS ARE PRESENT IN ATOMS
OF ALL ELEM.
Tuesday, October 8, 13
SO FAR WE’VE LEARNED…
• THOMPSON’S & MILLIKAN’S IDEAS:
– ATOMS ARE IN FACT DIVISABLE
– ELECTRONS ARE PRESENT IN ATOMS
OF ALL ELEM.
– ONE OF THE ATOM’S FUNDMNTL
PARTICLES IS NEG. CHARGED
Tuesday, October 8, 13
SO FAR WE’VE LEARNED…
• THOMPSON’S & MILLIKAN’S IDEAS:
– ATOMS ARE IN FACT DIVISABLE
– ELECTRONS ARE PRESENT IN ATOMS
OF ALL ELEM.
– ONE OF THE ATOM’S FUNDMNTL
PARTICLES IS NEG. CHARGED
– ATOMS ARE ELECTRICALLY
NEUTRAL, SO THERE MUST BE A (+)
CHARGE TO BALANCE OUT THE (–)
Tuesday, October 8, 13
SO FAR WE’VE LEARNED…
• THOMPSON’S & MILLIKAN’S IDEAS:
– ATOMS ARE IN FACT DIVISABLE
– ELECTRONS ARE PRESENT IN ATOMS
OF ALL ELEM.
– ONE OF THE ATOM’S FUNDMNTL
PARTICLES IS NEG. CHARGED
– ATOMS ARE ELECTRICALLY
NEUTRAL, SO THERE MUST BE A (+)
CHARGE TO BALANCE OUT THE (–)
– BECAUSE ELECTRONS ARE
BASICALLY MASSLESS THERE MUST
BE SOMETHING ELSE THAT
ACCOUNTS FOR THE ATOMS MASS.
Tuesday, October 8, 13
OTHER SIGNIFICANT
DISCOVERIES…
Tuesday, October 8, 13
OTHER SIGNIFICANT
DISCOVERIES…
• IN 1886, WHEN E. GOLDSTEIN
OBSERVED A CATHODE-RAY TUBE
AND FOUND RAYS TRAVELLING IN
THE OPPOSITE DIRECTION OF THAT
OF THE CATHODE RAYS
Tuesday, October 8, 13
OTHER SIGNIFICANT
DISCOVERIES…
• IN 1886, WHEN E. GOLDSTEIN
OBSERVED A CATHODE-RAY TUBE
AND FOUND RAYS TRAVELLING IN
THE OPPOSITE DIRECTION OF THAT
OF THE CATHODE RAYS
– HE CALLED THE RAYS CANAL RAYS
AND CONCLUDED THAT THEY WERE
COMPOSED OF POS. PARTICLES
Tuesday, October 8, 13
OTHER SIGNIFICANT
DISCOVERIES…
• IN 1886, WHEN E. GOLDSTEIN
OBSERVED A CATHODE-RAY TUBE
AND FOUND RAYS TRAVELLING IN
THE OPPOSITE DIRECTION OF THAT
OF THE CATHODE RAYS
– HE CALLED THE RAYS CANAL RAYS
AND CONCLUDED THAT THEY WERE
COMPOSED OF POS. PARTICLES
• IT WAS SOON DISCOVERED THAT
THE POSITIVE PARTICLES MASS IS
ABOUT 2000 TIMES THAT OF THE
ELECTRON
Tuesday, October 8, 13
OTHER SIGNIFICANT
DISCOVERIES…
Tuesday, October 8, 13
OTHER SIGNIFICANT
DISCOVERIES…
• IN 1932, THE ENGLISH PHYSICIST
JAMES CHADWICK CONFIRMED THE
EXISTANCE OF YET ANOTHER
SUBATOMIC PARTICLE.
Tuesday, October 8, 13
OTHER SIGNIFICANT
DISCOVERIES…
• IN 1932, THE ENGLISH PHYSICIST
JAMES CHADWICK CONFIRMED THE
EXISTANCE OF YET ANOTHER
SUBATOMIC PARTICLE.
– THE NEUTRON, WHICH IS A
PARTICLE WITH NO CHARGE
Tuesday, October 8, 13
OTHER SIGNIFICANT
DISCOVERIES…
• IN 1932, THE ENGLISH PHYSICIST
JAMES CHADWICK CONFIRMED THE
EXISTANCE OF YET ANOTHER
SUBATOMIC PARTICLE.
– THE NEUTRON, WHICH IS A
PARTICLE WITH NO CHARGE
– HAS A MASS NEARLY EQUAL TO
THAT OF THE PROTON
Tuesday, October 8, 13
OTHER SIGNIFICANT
DISCOVERIES…
• IN 1932, THE ENGLISH PHYSICIST
JAMES CHADWICK CONFIRMED THE
EXISTANCE OF YET ANOTHER
SUBATOMIC PARTICLE.
– THE NEUTRON, WHICH IS A
PARTICLE WITH NO CHARGE
– HAS A MASS NEARLY EQUAL TO
THAT OF THE PROTON
• THEREFORE THE SUBATOMIC
PARTICLES ARE THE ELECTRON,
PROTON, AND NEUTRON.
Tuesday, October 8, 13
electro
n
proton
neutro
n
Tuesday, October 8, 13
e
+
p
0
n
-1
+1
0
L
0
1
1
(g
)
A
M
A
SS
U
CT
A
SS
M
A
RE
LA
TI
VE
RG
E
A
CH
RE
LA
TI
VE
L
SY
M
BO
PA
RT
IC
LE
Properties of Subatomic Particles
9.11x1028
1.67x1024
1.67x1024
THE ATOMIC NUCLEUS
Tuesday, October 8, 13
THE ATOMIC NUCLEUS
• WHEN SUBATOMIC PARTICLES WERE
DISCOVERED, SCIENTISTS
WONDERED HOW THESE PARTICLES
WERE PUT TOGETHER IN AN ATOM.
Tuesday, October 8, 13
THE ATOMIC NUCLEUS
• WHEN SUBATOMIC PARTICLES WERE
DISCOVERED, SCIENTISTS
WONDERED HOW THESE PARTICLES
WERE PUT TOGETHER IN AN ATOM.
• THIS WAS A DIFFICULT QUESTION
TO ANSWER, GIVEN HOW TINY
ATOMS ARE.
Tuesday, October 8, 13
THE ATOMIC NUCLEUS
• WHEN SUBATOMIC PARTICLES WERE
DISCOVERED, SCIENTISTS
WONDERED HOW THESE PARTICLES
WERE PUT TOGETHER IN AN ATOM.
• THIS WAS A DIFFICULT QUESTION
TO ANSWER, GIVEN HOW TINY
ATOMS ARE.
• MOST SCIENTISTS THOUGHT IT
LIKELY THAT THE ELECTRONS WERE
EVENLY DISTRIBUTED
THROUGHOUT AN ATOM FILLED
UNIFORMLY WITH POSITIVELY
CHARGED MATERIAL.
Tuesday, October 8, 13
ERNEST RUTHERFORD
IN 1911,
RUTHERFORD
PERFORMED ONE OF
THE MOST BRILLIANT
INVESTIGATIONS EVER
CONCIEVED.
Tuesday, October 8, 13
ERNEST RUTHERFORD
HOW IS THE
ATOM BUILT?
IN 1911,
RUTHERFORD
PERFORMED ONE OF
THE MOST BRILLIANT
INVESTIGATIONS EVER
CONCIEVED.
Tuesday, October 8, 13
RUTHERFORD’S
FAMOUS EXPERIMENT
Tuesday, October 8, 13
RUTHERFORD’S
FAMOUS EXPERIMENT
• RUTHERFORD SET OUT TO TEST THE
THOMPSON MODEL OF THE ATOM
Tuesday, October 8, 13
RUTHERFORD’S
FAMOUS EXPERIMENT
• RUTHERFORD SET OUT TO TEST THE
THOMPSON MODEL OF THE ATOM
• THE TEST USED RELATIVELY
MASSIVE RADIOACTIVE ALPHA
PARTICLES
Tuesday, October 8, 13
RUTHERFORD’S
FAMOUS EXPERIMENT
• RUTHERFORD SET OUT TO TEST THE
THOMPSON MODEL OF THE ATOM
• THE TEST USED RELATIVELY
MASSIVE RADIOACTIVE ALPHA
PARTICLES
– ALPHA PARTICLES (α) ARE HELIUM
ATOMS THAT HAVE LOST THEIR
2 ELECTRONS AND HAVE A DOUBLE
POSITIVE CHARGE BECAUSE OF THE
2 REMAINING PROTONS
Tuesday, October 8, 13
Tuesday, October 8, 13
• IN THE EXPERIMENT, RUTHERFORD
DIRECTED A NARROW BEAM OF
ALPHA PARTICLES AT A VERY THIN
SHEET OF GOLD FOIL.
Tuesday, October 8, 13
• IN THE EXPERIMENT, RUTHERFORD
DIRECTED A NARROW BEAM OF
ALPHA PARTICLES AT A VERY THIN
SHEET OF GOLD FOIL.
–ACCORDING TO THE PREVAILING
THEORY, THE ALPHA PARTICLES
SHOULD HAVE PASSED EASILY
THROUGH THE GOLD, WITH ONLY A
SLIGHT DEFLECTION DUE TO THE
POSITIVE CHARGE THOUGHT TO BE
SPREAD OUT IN THE GOLD ATOMS.
Tuesday, October 8, 13
Tuesday, October 8, 13
Tuesday, October 8, 13
Tuesday, October 8, 13
WHAT HAPPENED?
Tuesday, October 8, 13
WHAT HAPPENED?
• THE MAJORITY OF THE α PARTICLES
PASSED STRAIGHT THROUGH THE
GOLD ATOMS, WITHOUT ANY
DEFLECTION
Tuesday, October 8, 13
WHAT HAPPENED?
• THE MAJORITY OF THE α PARTICLES
PASSED STRAIGHT THROUGH THE
GOLD ATOMS, WITHOUT ANY
DEFLECTION
• EVEN MORE SURPRISINGLY, A SMALL
FRACTION OF THE α PARTICLES
BOUNCED OFF THE GOLD FOIL
ATOMS AT VERY LARGE ANGLES
Tuesday, October 8, 13
WHAT HAPPENED?
• THE MAJORITY OF THE α PARTICLES
PASSED STRAIGHT THROUGH THE
GOLD ATOMS, WITHOUT ANY
DEFLECTION
• EVEN MORE SURPRISINGLY, A SMALL
FRACTION OF THE α PARTICLES
BOUNCED OFF THE GOLD FOIL
ATOMS AT VERY LARGE ANGLES
• SOME EVEN BOUNCED BACK
AT THE SOURCE
Tuesday, October 8, 13
Tuesday, October 8, 13
• BASED ON THE RESULTS,
RUTHERFORD SUGGESTED A NEW
THEORY OF THE ATOM.
Tuesday, October 8, 13
• BASED ON THE RESULTS,
RUTHERFORD SUGGESTED A NEW
THEORY OF THE ATOM.
• HE PROPOSED THAT THE ATOM IS
MOSTLY EMPTY SPACE
Tuesday, October 8, 13
• BASED ON THE RESULTS,
RUTHERFORD SUGGESTED A NEW
THEORY OF THE ATOM.
• HE PROPOSED THAT THE ATOM IS
MOSTLY EMPTY SPACE
–THIS EXPLAINED THE LACK OF
DEFLECTION OF SOME OF THE
PARTICLES
Tuesday, October 8, 13
• BASED ON THE RESULTS,
RUTHERFORD SUGGESTED A NEW
THEORY OF THE ATOM.
• HE PROPOSED THAT THE ATOM IS
MOSTLY EMPTY SPACE
–THIS EXPLAINED THE LACK OF
DEFLECTION OF SOME OF THE
PARTICLES
• HE CONCLUDED THAT ALL THE
POSITIVE CHARGE AND ALMOST ALL
THE MASS IS CONCENTRATED IN A
SMALL CORE
Tuesday, October 8, 13
• BASED ON THE RESULTS,
RUTHERFORD SUGGESTED A NEW
THEORY OF THE ATOM.
• HE PROPOSED THAT THE ATOM IS
MOSTLY EMPTY SPACE
–THIS EXPLAINED THE LACK OF
DEFLECTION OF SOME OF THE
PARTICLES
• HE CONCLUDED THAT ALL THE
POSITIVE CHARGE AND ALMOST ALL
THE MASS IS CONCENTRATED IN A
SMALL CORE
–HE CALLED THIS REGION THE
NUCLEUS
Tuesday, October 8, 13
Tuesday, October 8, 13
A LITTLE REVIEW!
Tuesday, October 8, 13
A LITTLE REVIEW!
• THERE ARE THREE FUNDAMENTAL
PARTICLES THAT TOGETHER MAKE
UP THE ATOM.
Tuesday, October 8, 13
A LITTLE REVIEW!
• THERE ARE THREE FUNDAMENTAL
PARTICLES THAT TOGETHER MAKE
UP THE ATOM.
– COMPOSED OF ELECTRONS,
PROTONS, AND NEUTRONS
Tuesday, October 8, 13
A LITTLE REVIEW!
• THERE ARE THREE FUNDAMENTAL
PARTICLES THAT TOGETHER MAKE
UP THE ATOM.
– COMPOSED OF ELECTRONS,
PROTONS, AND NEUTRONS
• THE PROTONS AND THE NEUTRONS
MAKE UP THE CENTER OF THE
ATOM
Tuesday, October 8, 13
A LITTLE REVIEW!
• THERE ARE THREE FUNDAMENTAL
PARTICLES THAT TOGETHER MAKE
UP THE ATOM.
– COMPOSED OF ELECTRONS,
PROTONS, AND NEUTRONS
• THE PROTONS AND THE NEUTRONS
MAKE UP THE CENTER OF THE
ATOM
– CENTER OF THE ATOM IS CALLED
THE NUCLEUS
Tuesday, October 8, 13
A LITTLE REVIEW!
• THERE ARE THREE FUNDAMENTAL
PARTICLES THAT TOGETHER MAKE
UP THE ATOM.
– COMPOSED OF ELECTRONS,
PROTONS, AND NEUTRONS
• THE PROTONS AND THE NEUTRONS
MAKE UP THE CENTER OF THE
ATOM
– CENTER OF THE ATOM IS CALLED
THE NUCLEUS
• THE PROTONS & NEUTRONS OCCUPY THE MASS OF THE ATOM
Tuesday, October 8, 13
Tuesday, October 8, 13
• THE ELECTRONS SURROUND THE
NUCLEUS AND OCCUPY MOST OF
THE ATOM’S VOLUME
Tuesday, October 8, 13
• THE ELECTRONS SURROUND THE
NUCLEUS AND OCCUPY MOST OF
THE ATOM’S VOLUME
• HOW, THEN, ARE ATOMS OF
HYDROGEN DIFFERENT FROM THOSE
OF OXYGEN?
Tuesday, October 8, 13
• THE ELECTRONS SURROUND THE
NUCLEUS AND OCCUPY MOST OF
THE ATOM’S VOLUME
• HOW, THEN, ARE ATOMS OF
HYDROGEN DIFFERENT FROM THOSE
OF OXYGEN?
–A SUBATOMIC PARTICLES FROM ONE
TYPE OF ATOM LOOKS LIKE
PARTICLES FROM OTHER ATOMS
Tuesday, October 8, 13
• THE ELECTRONS SURROUND THE
NUCLEUS AND OCCUPY MOST OF
THE ATOM’S VOLUME
• HOW, THEN, ARE ATOMS OF
HYDROGEN DIFFERENT FROM THOSE
OF OXYGEN?
–A SUBATOMIC PARTICLES FROM ONE
TYPE OF ATOM LOOKS LIKE
PARTICLES FROM OTHER ATOMS
electron for H
electron for C
electron for O
Tuesday, October 8, 13
• THE ELECTRONS SURROUND THE
NUCLEUS AND OCCUPY MOST OF
THE ATOM’S VOLUME
• HOW, THEN, ARE ATOMS OF
HYDROGEN DIFFERENT FROM THOSE
OF OXYGEN?
–A SUBATOMIC PARTICLES FROM ONE
TYPE OF ATOM LOOKS LIKE
PARTICLES FROM OTHER ATOMS
electron for H
electron for C
electron for O
Tuesday, October 8, 13
proton from H
proton from C
proton from O
Tuesday, October 8, 13
• IT’S THE NUMBERS OF PROTONS IN
AN ATOM THAT MAKES ATOMS
DIFFERENT.
Tuesday, October 8, 13
• IT’S THE NUMBERS OF PROTONS IN
AN ATOM THAT MAKES ATOMS
DIFFERENT.
–AN OXYGEN ATOM HAS 8 PROTONS
IN ITS NUCLEUS
Tuesday, October 8, 13
• IT’S THE NUMBERS OF PROTONS IN
AN ATOM THAT MAKES ATOMS
DIFFERENT.
–AN OXYGEN ATOM HAS 8 PROTONS
IN ITS NUCLEUS
–A HYDROGEN ATOM HAS 1 PROTON
IN ITS NUCLEUS
Tuesday, October 8, 13
• IT’S THE NUMBERS OF PROTONS IN
AN ATOM THAT MAKES ATOMS
DIFFERENT.
–AN OXYGEN ATOM HAS 8 PROTONS
IN ITS NUCLEUS
–A HYDROGEN ATOM HAS 1 PROTON
IN ITS NUCLEUS
• THE ATOMIC NUMBER OF AN
ELEMENT IS THE NUMBER OF
PROTONS IN THE NUCLEUS OF AN
ATOM OF THAT ELEMENT
Tuesday, October 8, 13
• IT’S THE NUMBERS OF PROTONS IN
AN ATOM THAT MAKES ATOMS
DIFFERENT.
–AN OXYGEN ATOM HAS 8 PROTONS
IN ITS NUCLEUS
–A HYDROGEN ATOM HAS 1 PROTON
IN ITS NUCLEUS
• THE ATOMIC NUMBER OF AN
ELEMENT IS THE NUMBER OF
PROTONS IN THE NUCLEUS OF AN
ATOM OF THAT ELEMENT
–SINCE OXYGEN’S NUCLEUS HAS
8 PROTONS ITS ATOMIC # IS 8
Tuesday, October 8, 13
• IT’S THE NUMBERS OF PROTONS IN
AN ATOM THAT MAKES ATOMS
DIFFERENT.
–AN OXYGEN ATOM HAS 8 PROTONS
IN ITS NUCLEUS
–A HYDROGEN ATOM HAS 1 PROTON
IN ITS NUCLEUS
• THE ATOMIC NUMBER OF AN
ELEMENT IS THE NUMBER OF
PROTONS IN THE NUCLEUS OF AN
ATOM OF THAT ELEMENT
–SINCE OXYGEN’S NUCLEUS HAS
8 PROTONS ITS ATOMIC # IS 8
• THE PROTONS IDENTIFY THE TYPE
OF ATOM, THE ONLY ATOM WITH
8 PROTONS IS OXYGEN
Tuesday, October 8, 13
Tuesday, October 8, 13
ATOMS OF THE 1ST TEN ATOMS
NAME
SYMBOL
Hydrogen H
Helium
He
Lithium
Li
Beryllium Be
Boron
B
Carbon
C
Nitrogen N
Oxygen
O
Fluorine F
Neon
Ne
Tuesday, October 8, 13
ATOMIC #
1
2
3
4
5
6
7
8
9
10
PROTONS
1
2
3
4
5
6
7
8
9
10
NEUTRONS
0
2
4
5
6
6
7
8
10
10
MASS #
1
4
7
9
11
12
14
16
19
20
ELECTRONS
1
2
3
4
5
6
7
8
9
10
Tuesday, October 8, 13
• FOR EACH ELEMENT LISTED, THE
NUMBER OF PROTONS EQUALS THE
NUMBER OF ELECTRONS
Tuesday, October 8, 13
• FOR EACH ELEMENT LISTED, THE
NUMBER OF PROTONS EQUALS THE
NUMBER OF ELECTRONS
–REMEMBER ATOMS ARE
ELECTRICALLY NEUTRAL
Tuesday, October 8, 13
• FOR EACH ELEMENT LISTED, THE
NUMBER OF PROTONS EQUALS THE
NUMBER OF ELECTRONS
–REMEMBER ATOMS ARE
ELECTRICALLY NEUTRAL
• IN AN ATOM, THE NUMBER OF
ELECTRONS MUST EQUAL THE
NUMBER OF PROTONS
Tuesday, October 8, 13
• FOR EACH ELEMENT LISTED, THE
NUMBER OF PROTONS EQUALS THE
NUMBER OF ELECTRONS
–REMEMBER ATOMS ARE
ELECTRICALLY NEUTRAL
• IN AN ATOM, THE NUMBER OF
ELECTRONS MUST EQUAL THE
NUMBER OF PROTONS
• A HYDROGEN ATOM HAS 1 ELECTRN
Tuesday, October 8, 13
• FOR EACH ELEMENT LISTED, THE
NUMBER OF PROTONS EQUALS THE
NUMBER OF ELECTRONS
–REMEMBER ATOMS ARE
ELECTRICALLY NEUTRAL
• IN AN ATOM, THE NUMBER OF
ELECTRONS MUST EQUAL THE
NUMBER OF PROTONS
• A HYDROGEN ATOM HAS 1 ELECTRN
• AN OXYGEN ATOM HAS 8 ELECTRNS
Tuesday, October 8, 13
• FOR EACH ELEMENT LISTED, THE
NUMBER OF PROTONS EQUALS THE
NUMBER OF ELECTRONS
–REMEMBER ATOMS ARE
ELECTRICALLY NEUTRAL
• IN AN ATOM, THE NUMBER OF
ELECTRONS MUST EQUAL THE
NUMBER OF PROTONS
• A HYDROGEN ATOM HAS 1 ELECTRN
• AN OXYGEN ATOM HAS 8 ELECTRNS
• THE MASS OF AN ATOM IS CONCEN.
IN ITS NUCLEUS AND DEPENDS ON
THE NUMER OF PROTONS AND
NEUTRONS
Tuesday, October 8, 13
Tuesday, October 8, 13
• THE TOTAL NUMBER OF PROTONS
AND NEUTRONS IN AN ATOM IS
CALLED THE MASS NUMBER
Tuesday, October 8, 13
• THE TOTAL NUMBER OF PROTONS
AND NEUTRONS IN AN ATOM IS
CALLED THE MASS NUMBER
–A CARBON ATOM, WHICH HAS 6
PROTONS AND 6 NEUTRONS, HAS A
MASS NUMBER OF 12
Tuesday, October 8, 13
• THE TOTAL NUMBER OF PROTONS
AND NEUTRONS IN AN ATOM IS
CALLED THE MASS NUMBER
–A CARBON ATOM, WHICH HAS 6
PROTONS AND 6 NEUTRONS, HAS A
MASS NUMBER OF 12
• IF YOU KNOW THE ATOMIC NUMBER
AND MASS NUMBER OF AN ATOM OF
ANY ELEMENT, YOU CAN DETERMINE
THE ATOM’S COMPOSITION
Tuesday, October 8, 13
• THE TOTAL NUMBER OF PROTONS
AND NEUTRONS IN AN ATOM IS
CALLED THE MASS NUMBER
–A CARBON ATOM, WHICH HAS 6
PROTONS AND 6 NEUTRONS, HAS A
MASS NUMBER OF 12
• IF YOU KNOW THE ATOMIC NUMBER
AND MASS NUMBER OF AN ATOM OF
ANY ELEMENT, YOU CAN DETERMINE
THE ATOM’S COMPOSITION
• THE COMPOSITION OF ANY ATOM
CAN BE REPRESENTED IN
SHORTHAND NOTATION:
Tuesday, October 8, 13
CHEMICAL COMPOSITION
SHORTHAND
Cl
MASS
NUMBER
35
ATOMIC
NUMBER
17
NUMBER OF
PROTONS
Tuesday, October 8, 13
CHEMICAL COMPOSITION
SHORTHAND
# OF PROTONS
+
# OF NEUTRONS
Cl
MASS
NUMBER
35
ATOMIC
NUMBER
17
NUMBER OF
PROTONS
Tuesday, October 8, 13
Tuesday, October 8, 13
ISOTOPES
Tuesday, October 8, 13
ISOTOPES
• EVERY CHLORINE ATOM HAS 17
PROTONS, WITHOUT EXCEPTION,
Tuesday, October 8, 13
ISOTOPES
• EVERY CHLORINE ATOM HAS 17
PROTONS, WITHOUT EXCEPTION,
– HOWEVER, NOT EVERY CHLORINE
ATOM HAS
18
NEUTRONS.
Tuesday, October 8, 13
ISOTOPES
• EVERY CHLORINE ATOM HAS 17
PROTONS, WITHOUT EXCEPTION,
– HOWEVER, NOT EVERY CHLORINE
ATOM HAS
18
NEUTRONS.
–ATOMS WITH THE SAME NUMBER OF
PROTONS BUT CONTAIN DIFFERENT
NUMBERS OF NEUTRONS ARE
CALLED ISOTOPES.
Tuesday, October 8, 13
ISOTOPES
• EVERY CHLORINE ATOM HAS 17
PROTONS, WITHOUT EXCEPTION,
– HOWEVER, NOT EVERY CHLORINE
ATOM HAS
18
NEUTRONS.
–ATOMS WITH THE SAME NUMBER OF
PROTONS BUT CONTAIN DIFFERENT
NUMBERS OF NEUTRONS ARE
CALLED ISOTOPES.
• BECAUSE ISOTOPES OF AN ELEMENT
HAVE DIFFERENT NUMBERS OF
NEUTRONS THEY HAVE DIFFERENT
MASS NUMBERS.
Tuesday, October 8, 13
BERYLLIUM
ISOTOPES
proton
neutron
electron
Tuesday, October 8, 13
• ISOTOPES ARE CHEMICALLY ALIKE
BECAUSE THEY HAVE IDENTICAL
NUMBERS OF PROTONS AND
ELECTRONS
BERYLLIUM
ISOTOPES
proton
neutron
electron
Tuesday, October 8, 13
• ISOTOPES ARE CHEMICALLY ALIKE
BECAUSE THEY HAVE IDENTICAL
NUMBERS OF PROTONS AND
ELECTRONS
–IT’S THE ELECTRONS AND PROTONS
THAT ARE RESPONSIBLE FOR
CHEMICAL BEHAVIOR
BERYLLIUM
ISOTOPES
proton
neutron
electron
Tuesday, October 8, 13
Tuesday, October 8, 13
EXAMPLE OF AN ISOTOPE
Cl
Cl
35
37
17
17
Tuesday, October 8, 13
EXAMPLE OF AN ISOTOPE
ATOMIC MASS
Cl
Cl
35
37
17
17
Tuesday, October 8, 13
EXAMPLE OF AN ISOTOPE
ATOMIC MASS
Cl
Cl
35
37
17
17
ATOMIC NUMBER
Tuesday, October 8, 13
EXAMPLE OF AN ISOTOPE
ATOMIC MASS
Cl
Cl
35
37
17
17
18 NEUTRONS
ATOMIC NUMBER
Tuesday, October 8, 13
EXAMPLE OF AN ISOTOPE
ATOMIC MASS
Cl
Cl
35
37
17
17
18 NEUTRONS
20 NEUTRONS
ATOMIC NUMBER
Tuesday, October 8, 13
IONS
Tuesday, October 8, 13
IONS
• AN ELEMENT’S ATOMS ARE NOT
ALWAYS NEUTRAL IN CHARGE.
Tuesday, October 8, 13
IONS
• AN ELEMENT’S ATOMS ARE NOT
ALWAYS NEUTRAL IN CHARGE.
– WHEN AN ATOM LOSES OR GAINS
ONE OR MORE OF ITS ELECTRONS IT
BECOMES ION.
Tuesday, October 8, 13
IONS
• AN ELEMENT’S ATOMS ARE NOT
ALWAYS NEUTRAL IN CHARGE.
– WHEN AN ATOM LOSES OR GAINS
ONE OR MORE OF ITS ELECTRONS IT
BECOMES ION.
• AN ION THAT HAS MORE
ELECTRONS THAN PROTONS HAS A
NEGATIVE ELECTRICAL CHARGE
Tuesday, October 8, 13
IONS
• AN ELEMENT’S ATOMS ARE NOT
ALWAYS NEUTRAL IN CHARGE.
– WHEN AN ATOM LOSES OR GAINS
ONE OR MORE OF ITS ELECTRONS IT
BECOMES ION.
• AN ION THAT HAS MORE
ELECTRONS THAN PROTONS HAS A
NEGATIVE ELECTRICAL CHARGE
• AN ION THAT HAS FEWER
ELECTRONS THAN PROTONS HAS A
POSITIVE ELECTRICAL CHARGE
Tuesday, October 8, 13
IONS
• AN ELEMENT’S ATOMS ARE NOT
ALWAYS NEUTRAL IN CHARGE.
– WHEN AN ATOM LOSES OR GAINS
ONE OR MORE OF ITS ELECTRONS IT
BECOMES ION.
• AN ION THAT HAS MORE
ELECTRONS THAN PROTONS HAS A
NEGATIVE ELECTRICAL CHARGE
• AN ION THAT HAS FEWER
ELECTRONS THAN PROTONS HAS A
POSITIVE ELECTRICAL CHARGE
NOTE: IT’S THE PROTONS THAT DEFINE
THE TYPE OF ATOM IT IS, BUT THE
ELECTRONS DEFINE THE ATOM’S
CHARGE.
Tuesday, October 8, 13
Tuesday, October 8, 13
SOME ATOMS
GAIN ELECTRONS
ATOM’S IONIC CHARGE =
# PROTONS - # ELECTRONS
-
-
-
-
O
Tuesday, October 8, 13
-
-
-
-
-
-
-
-
-
O-2
-
ATOMS, IONS, AND ISOTOPES
ATOMS
NEUTRAL AND ARE DEFINED BY
THE # OF PROTONS IN THEIR
NUCLEUS
3 p+ = Li ATOM, ETC.
IONS
HAVE AN ELECTRICAL CHARGE
DETERMINED BY
# PROTONS - # ELECTRONS
N-2 = 7 p+ - 9 e- ; ETC.
ISOTOPES
TWO ATOMS WITH THE SAME #
OF PROTONS, BUT DIFFERENT #’S
OF NEUTRONS OR MASSES
CALCIUM-40 & CALCIUM-44
Tuesday, October 8, 13