- WELCOME TO ATOMS AND ELEMENTS PART ZERO.
THIS WILL BE OUR INTRODUCTION TO ATOMIC STRUCTURE.
LET'S GET STARTED.
NOW, ONE OF THE MOST IMPORTANT CONCEPTS
THAT WE NEED TO REALLY BECOME COMFORTABLE WITH RIGHT AWAY
IS THE IDEA OF ELECTROSTATICS.
IT'S ALSO REFERRED TO AS COULOMBIC FORCES
BUT WE'LL JUST STAY WITH ELECTROSTATICS,
IT'S ABOUT CHARGE.
SO, CHARGE DRIVES EVERYTHING IN CHEMISTRY,
SO, OPPOSITES ATTRACT.
SO, WHEN WE HAVE OPPOSITE CHARGES,
THEY CANNOT RESIST EACH OTHER. THEY WANT TO BE TOGETHER
IT DOESN'T MATTER WHAT THE CIRCUMSTANCES,
POSITIVE AND NEGATIVE LOVE TO COME TOGETHER
AND LIKES REPEL.
SO, WHETHER WE HAVE TWO POSITIVES
OR WE HAVE TWO NEGATIVES,
THEY DO NOT WANT TO BE NEXT TO EACH OTHER,
SO, THEY ARE GOING TO REPEL.
AND SO, THIS IDEA OF ELECTROSTATIC ATTRACTION
AND REPULSION IS A DRIVING FORCE
IN EVERYTHING WE'RE GOING TO LOOK AT.
AND SO, AS WE BEGIN TO TALK ABOUT THE STRUCTURE OF THE ATOM,
I WANT YOU TO THINK ABOUT AND KEEP IN MIND THE DYNAMICS
BETWEEN POSITIVE AND NEGATIVE CHARGE, ALL RIGHT?
THIS IS A DANCE WE'RE GOING TO FOLLOW ALL SEMESTER.
NOW, I'M GOING TO GO THROUGH A LITTLE HISTORY HERE.
DON'T WORRY, THIS ISN'T A HISTORY CLASS.
DON'T WORRY ABOUT MEMORIZING ANY DATES OR ANYTHING.
I THINK THAT THE HISTORICAL CONTEXT GIVES US A SENSE
AND REFLECTS THE STRUCTURE OF THE ATOM.
SO, WE'RE GOING TO LOOK AT IT IN THAT CONTEXT,
BUT DON'T SWEAT THE DATES, ALL RIGHT?
SO, WE HAVE BEEN DEBATING WHAT WE'RE MADE OF
AT A PHYSICAL LEVEL AND A METAPHYSICAL LEVEL
FOR CENTURIES, FOR MILLENNIA.
SO, THE WORD ATOM IS VERY OLD. IT COMES FROM OVER 400 B.C.,
IT COMES FROM THE GREEK WORD, 'ATOMOS'
WHICH MEANS UNCUT OR INDIVISIBLE.
AND IT WAS COINED BY DEMOCRITUS, BECAUSE HE WAS THE PROPONENT
OF DISCONTINUOUS MATTER CONCEPTS.
SO, WHAT EXACTLY DOES THAT MEAN, DISCONTINUOUS MATTER?
I'M GOING TO DO A LITTLE DEMO HERE FOR A MOMENT.
SO, LET'S LOOK AT THIS PENCIL.
SO, BACK IN DEMOCRITUS'S TIME, THERE WAS A BIG DEBATE,
SO, ONE GROUP OF PEOPLE SAID WE COULD CUT THIS PENCIL IN HALF
AND CUT THIS PENCIL IN HALF AND CUT THIS PENCIL IN HALF
AND WE COULD CUT IN HALF INTO INFINITY.
AND WE COULD NEVER STOP.
WE COULD CUT IN HALF AS LONG AS WE WANT IT.
BUT DEMOCRITUS SAID, NO, THAT IF WE KEPT CUTTING,
EVENTUALLY, WE WOULD GET TO THIS ATOMOS WHERE WE COULD
NOT BREAK IT DOWN ANY FURTHER.
AND SO, AT A CHEMICAL LEVEL, DEMOCRITUS WAS CORRECT
WE CALL IT THE ATOM TODAY.
LET'S SEE WHAT ELSE HAPPENED.
WE JUST REMEMBER NO COMPUTERS, NO INTERNET,
NO AGE OF INFORMATION.
SO, 2200 YEARS LATER, DALTON, A VERY THOUGHTFUL MAN,
HE IS OBSERVING AND THINKING ABOUT WHAT WE KNOW TODAY,
AND HE COMES UP WITH AN ATOMIC THEORY, RIGHT?
HE SAYS, ELEMENTS ARE MADE OF TINY PARTICLES CALLED ATOMS,
HE AGREED WITH DEMOCRITUS.
ALL ATOMS OF A GIVEN ELEMENT ARE IDENTICAL.
SO, THIS FIRST ONE, WE STILL HOLD THIS TRUE,
WHICH IT TURNS OUT THIS ASPECT OF THE THEORY IS WRONG.
THE REASON FOR THAT IS ISOTOPES. WE WILL COME BACK TO THOSE.
THOSE WERE IMPORTANT.
AND DALTON ALSO SAID THE ATOMS OF A GIVEN ELEMENT ARE DIFFERENT
FROM THOSE OF ANY OTHER ELEMENT.
THAT'S ABSOLUTELY TRUE.
ATOMS OF ONE ELEMENT CAN COMBINE WITH ATOMS OF OTHER ELEMENTS
TO FORM COMPOUNDS.
THIS IS TRUE.
AND WE TALK ABOUT THE COMPOUNDS AS A FIXED RATIO OF ATOMS.
AND THEN, LAST BUT NOT THE LEAST,
ATOMS ARE INDIVISIBLE BY CHEMICAL PROCESSES,
SO, THEY'RE NOT CREATED OR DESTROYED.
SO, WE WILL TALK ABOUT NUCLEAR CHEMISTRY IN THIS COURSE
AND THEN, THIS DOES NOT APPLY.
SO, RIGHT NOW, WE'RE TALKING ABOUT CHEMICAL PROCESSES.
SO, IT TOOK A LONG TIME TO MAKE A SIGNIFICANT PROGRESS
FROM DEMOCRITUS TO DALTON, BUT THEN IN ABOUT 80 YEARS,
J.J. THOMSON, HE SHOWED THAT ATOMS CONTAIN NEGATIVE PARTICLES
SO, HERE'S THAT DANCE OF CHARGE THAT WE STARTED TO TALK ABOUT
AT THE VERY BEGINNING, RIGHT?
SO, ELECTRONS ARE A LOWERCASE E
WITH THE UPPERCASE MINUS, THOSE ARE ELECTRONS.
BUT THEN, ATOMS ARE NEUTRAL.
SO, IF ATOMS ARE NEUTRAL
AND WE FOUND AN OBJECT WITHIN THEM THAT HAS A NEGATIVE CHARGE,
THEN THERE MUST BE SOMETHING THAT HAS POSITIVE CHARGE.
AND SO, THOSE ARE THE PROTONS.
INTERESTINGLY FOR SOME REASON, WE DON'T PUT THE PLUS
ON THE P FOR PROTONS LIKE WE DO THE E FOR ELECTRONS,
I DON'T KNOW WHAT THAT'S ABOUT
BUT JUST SO YOU'RE NOT EXPECTING IT, OKAY?
WE JUST KNOW THAT PROTONS ARE PLUS ONE.
SO THEN, IN ABOUT THE SAME TIME, LORD KELVIN,
WHO WE'VE NAMED A TEMPERATURE UNIT AFTER,
HE PROPOSED THE PLUM PUDDING MODEL FOR THE ATOM.
AND I LIKE TO BRING THIS UP BECAUSE I THINK IT'S IMPORTANT,
IT SHOWS THAT THEORIES COME AND GO,
THE PLUM PUDDING MODEL WAS THE STATE OF THE ART THEORY
FOR A DECADE.
AND RUTHERFORD, HE WAS REALLY EXPLORING KELVIN'S IDEAS
ABOUT THIS PLUM PUDDING MODEL, AND SO, HE DID AN EXPERIMENT.
SO, LET'S LOOK AT HOW LORD KELVIN'S THEORY
AND RUTHERFORD'S--HOW IT ALL COME TOGETHER IN THE EXPERIMENT.
HELP US SORTED OUT, ALL RIGHT?
SO, THIS WOULD BE THE KELVIN PLUM PUDDING HERE,
SO, PLUM PUDDING WAS A DESSERT, BASICALLY--LITERALLY A PUDDING,
WITH RAISINS IN IT.
THE MODERN DAY EQUIVALENT WOULD PROBABLY BE MUFFIN
WITH, LIKE, CHOCOLATE CHIPS OR RAISINS, OR BLUEBERRIES, RIGHT?
SO, ACCORDING TO KELVIN'S THEORY,
THE POSITIVE CHARGE WAS THE PLUM PUDDING, ALL RIGHT?
AND THEN, THE ELECTRONS WERE THE LITTLE RAISINS
OR CHOCOLATE CHIPS NESTLED INTO THE MUFFIN OR THE PUDDING,
SO THEN, RUTHERFORD WENT TO TEST THIS ATOMIC THEORY.
SO, WHAT DID RUTHERFORD DO?
WELL, HE TOOK A SOURCE OF ALPHA PARTICLES,
AND JUST TO LET YOU KNOW, ALPHA PARTICLES HAVE A +2 CHARGE,
AND SO, WE HAVE THIS BEAM OF ALPHA PARTICLES
AND THEN HE PUT A THIN METAL FOIL.
AND SO, RUTHERFORD SAID,
WELL, IF THE PLUM PUDDING MODEL IS CORRECT,
THEN THE POSITIVE CHARGE IS DELOCALIZED
THROUGH THE ENTIRE ATOM,
THEN THE POSITIVE CHARGE OF THESE ALPHA PARTICLES
WILL JUST SAIL RIGHT THROUGH THE ATOMS IN THE METAL FOIL.
AND INITIALLY, THAT'S EXACTLY WHAT HAPPENED.
MOST OF THE PARTICLES PASSED STRAIGHT THROUGH.
SO, IT LOOKED LIKE THE PLUM PUDDING MODEL
WAS THE CORRECT MODEL.
BUT THE LONGER RUTHERFORD DID THE EXPERIMENT,
HE STARTED TO NOTICE THAT, DING, THERE STARTED TO BE SOME
EXPOSURE HERE AND HERE FROM THESE ALPHA PARTICLES.
SO, THESE ALPHA PARTICLES WERE GETTING SCATTERED.
SO, REMEMBER, IF WE HAVE TWO POSITIVE CHARGES,
THEY REPEL EACH OTHER.
SO, WHAT RUTHERFORD OBSERVED WAS THAT THERE WAS LOCALIZED
POSITIVE CHARGE CAUSING THESE ALPHA PARTICLES TO REFLECT
OR BE DEFLECTED.
AND THAT LED TO RUTHERFORD'S NUCLEAR ATOM.
AND SO, WE ALL KNOW THAT THIS IS STILL THE ACCEPTED FORM, RIGHT?
SO, NOW, WE KNOW THAT THE POSITIVE CHARGES
LOCALIZED IN THE NUCLEUS AND THEN THAT'S WHAT CAUSES
THE DEFLECTION OF THE ALPHA PARTICLES.
HOWEVER, IT'S IMPORTANT TO KEEP IN MIND, RIGHT,
THAT MOST OF THE ALPHA PARTICLES STILL SAILED STRAIGHT THROUGH,
SO, IF THE NUCLEUS, THERE'S-- THAT MEANS THERE'S A LOT
OF EMPTY SPACE, ALL RIGHT?
SO, LET'S SAY WE MADE THE NUCLEUS THE SIZE OF A GRAPE,
THEN, IF YOU IMAGINE A NUCLEUS AS BEING A SIZE OF A GRAPE,
THE ELECTRONS, RIGHT?
THE ELECTRONS ARE UP TO ONE MILE AWAY, ALL RIGHT?
SO, BASICALLY, ATOMS ARE MOSTLY EMPTY.
WHY DOES IT FEEL SO HARD, RIGHT?
IT FEEL SO HARD, WE'RE GOING TO SEE,
BECAUSE THOSE ELECTRONS ARE BUSY WHIRLING ABOUT,
SO, THE SOLIDNESS THAT WE FEEL REALLY IS AN ILLUSION.
WE ARE MOSTLY EMPTY SPACE.
WE'LL KEEP GOING.
SO ANOTHER EIGHT YEARS LATER,
RUTHERFORD DETERMINED THAT THE PROTON HAD THE SAME MAGNITUDE
OF CHARGE AS THE ELECTRON,
SO, THAT'S REALLY HELPFUL.
SO, WE'RE JUST GOING TO CALL THEM + AND -1.
AND THEN, IT TOOK ANOTHER 13 YEARS FOR THE LAST BIT
TO COME ABOUT.
HERE WE GO.
SO, IN 1932, RUTHERFORD DEMONSTRATED THE EXISTENCE
OF NEUTRONS, RIGHT? AND THEY'RE NEUTRAL.
THEY DON'T HAVE ANY CHARGE, RIGHT?
AND SO, THEY WERE THE LAST TO FIND
BECAUSE THEY'RE THE HARDEST TO FIND
BECAUSE THEY DON'T INTERACT.
POSITIVE AND NEGATIVE WILL INTERACT BUT NEUTRAL,
IT'S ALOOF.
AND THEN, THIS WAS THE POSTULATE OF DALTON'S ATOMIC THEORY
THAT WE SHOWED WAS WRONG. IT WAS THIS IDEA OF ISOTOPES,
ATOMS WITH THE SAME NUMBER OF PROTONS
BUT DIFFERENT NUMBERS OF NEUTRONS ARE ISOTOPES.
AND WE ARE GOING TO LOOK MORE CLOSELY AT THOSE IN THIS COURSE
BUT FOR RIGHT NOW, LET'S TAKE A BREATH AND SAY,
OKAY. SO, WHAT DID WE LEARN SINCE 1932?
WELL, WE LEARNED A LOT BUT FOR THESE THREE SUBATOMIC PARTICLES,
WE'RE IN PRETTY GOOD SHAPE.
WE HAVE THE ELECTRON, THE PROTON, AND THE NEUTRON,
WE FOUND THE ELECTRON FIRST. IT HAD NEGATIVE CHARGE, RIGHT?
THEN RUTHERFORD FOUND OUT THAT PROTONS AND ELECTRONS
HAD EQUAL AND OPPOSITE CHARGE,
THEN OF COURSE THE NEUTRON IS NEUTRAL.
NOW, MASS...WE'RE JUST GOING TO ARBITRARILY GIVE THE ELECTRON
A MASS OF ONE.
AND IF WE DO THAT, THE PROTONS ARE ALMOST 2,000 TIMES HEAVIER
AND THE NEUTRONS ARE SLIGHTLY MORE HEAVIER THAN THE PROTONS
BUT THIS--FOR OUR PURPOSES, THIS IS ENOUGH.
SO, BASICALLY WHAT THIS TELLS US IS THAT THE ELECTRON MASS
IS NEGLIGIBLE. WE CAN REALLY IGNORE IT.
WHEN WE'RE LOOKING AT THE MASS OF AN ATOM,
IT'S THE PROTONS AND NEUTRONS THAT CREATE THE MASS.
OKAY. SO, NOW, WE NEED SOME TERMS TO DESCRIBE ATOM
SO THAT WE CAN COMPARE THEM, ALL RIGHT?
FOR ATOMIC NUMBER, WE'RE GOING TO USE THIS SYMBOL Z
AND SO THAT REPRESENTS THE NUMBER OF PROTONS
IN AN ATOM,
AND SO THE ATOMIC NUMBER IS UNIQUE TO EACH ELEMENT.
SO, IF I'M AN ELEMENT AND I ONLY HAVE ONE PROTON,
I HAVE TO BE HYDROGEN.
ELEMENTS WITH ATOMS WITH ONLY ONE PROTON
ARE ALWAYS THE ELEMENT, HYDROGEN, RIGHT?
THIS IS HOW WE KNOW WHAT ELEMENT WE'RE TALKING ABOUT.
NOW, THE MASS NUMBER THAT WE GAVE THAT THE SYMBOL A,
AND JUST REMEMBER, I DIDN'T MAKE UP THIS SYMBOLS,
I THOUGHT THEY WERE KIND OF GOOFY TOO
WHEN I WAS LEARNING THEM BUT HERE WE ARE.
SO, THAT'S THE NUMBER OF PROTONS PLUS THE NUMBER OF NEUTRONS,
AND WE SEE THAT THAT MAKE SENSE, RIGHT?
BECAUSE WHEN WE LOOK AT THE STRUCTURE OF AN ATOM,
IT'S THE PROTONS AND THE NEUTRONS THAT CREATE
THE ATOMIC MASS, RIGHT?
SO, MASS NUMBER IS A GOOD NAME.
OKAY. NOW, ISOTOPES. ALL RIGHT.
SO, WE TALK ABOUT ISOTOPES OF AN ELEMENT.
SO, FOR TALKING ABOUT ISOTOPES OF AN ELEMENT,
THAT MEANS ATOMS OF THE SAME ELEMENT, RIGHT?
SO THAT MEANS THEY HAVE TO HAVE THE SAME Z,
SAME NUMBER OF PROTONS, RIGHT?
BUT DIFFERENT, WHAT?
DIFFERENT VALUES OF A.
THE PROTONS PLUS THE NEUTRONS, RIGHT?
SO, IF THIS IS THE SAME, RIGHT?
WHAT'S VARYING IN ISOTOPES, THIS IS WHAT VARIES,
THE NUMBER OF NEUTRONS,
LET ME SLIDE THIS UP.
IT'S THE NUMBER OF NEUTRONS THAT VARY.
THAT CREATES DIFFERENCES IN THE MASS NUMBER,
SO, AND WE WILL TALK MORE ABOUT ISOTOPES
IN THE COMING VIDEOS,
SO, I DON'T WANT TO SAY TOO MUCH NOW BECAUSE WE'LL GET TO MORE,
SO, THEN LET'S PUT THIS ALL TOGETHER, RIGHT?
SO, WE'LL GO--THE NUCLEUS, WE'LL PUT THAT IN THE CENTER,
RIGHT? THERE'S OUR NUCLEUS. SO, WHEN WE SEE THE NUCLEUS,
RIGHT, WE SEE THAT THERE'S GOING TO BE PROTONS
AND NEUTRONS PRESENT, ALL RIGHT?
AND THIS IS WHAT CREATES THE MASS OF THE ELEMENT,
AND THEN THE ELECTRONS RIGHT THERE UP TO A MILE AWAY
IF THE NUCLEUS WAS THE SIZE OF A GRAPE, RIGHT?
SO, HERE IS THE ELECTRONS, THE LITTLE MUFFINS OR RAISINS,
SO, WHAT DO THE ELECTRONS DO?
THEY CREATE THE SIZE, OKAY?
YOU COULD THINK OF IT AS THE VOLUME AS WELL,
RIGHT? SO, WHEN WE THINK ABOUT MATTER, RIGHT,
WE'RE THINKING ABOUT MASS AND VOLUME
AND SO, WE WANT TO LINK THAT TO OUR ATOMIC STRUCTURE.
SO, WELL, LET'S LOOK AT THAT ON THE NEXT PAGE.
LET'S BRIDGE THIS TOGETHER.
LET'S LINK THE MICROSCOPIC AND THE MACROSCOPIC TOGETHER, OKAY?
SO, ATOMS ARE THE BUILDING BLOCKS OF MATTER
AND MATTER IS DEFINED AS ANYTHING WITH MASS AND VOLUME,
SO, WHAT'S THE RELATIONSHIP BETWEEN ATOMIC STRUCTURE
AND MATTER?
SO, WE'RE LOOKING AT-- HOW DO I WANT THIS?
YOUR ATOMS, RIGHT, AND MATTER.
SO, ATOMS BUILD MATTER, RIGHT?
SO, IT'S THE PROTONS AND NEUTRONS IN THE ATOMS,
THOSE CREATE THE MASS OF MATTER,
AND THE ELECTRONS CREATE THE VOLUME OF MATTER,
BECAUSE THE ELECTRONS CREATE THE VOLUME OF EACH ATOM.
SO, NOW, LET'S LOOK AT HOW THIS INFORMATION IS COMMUNICATED
TO US ON THE PERIODIC TABLE.
SO, IF WE LOOK RIGHT ABOVE EACH SYMBOL, WE SEE A WHOLE NUMBER,
INCREASING BY ONE, ALL RIGHT?
THESE VALUES, THESE ARE THE ATOMIC NUMBER.
THIS IS Z, THE ATOMIC NUMBER,
AND REMEMBER WHAT IS THAT? THAT'S THE NUMBER OF PROTONS.
OKAY. NOW, WE HAVE ALL THE SYMBOLS,
NOW, UNDERNEATH, I KNOW THIS IS VERY HARD TO SEE
BUT YOU HAVE YOUR COPY THAT YOU'RE WORKING WITH.
WE HAVE ALL OF THESE NUMBERS DOWN BELOW
AND THESE NUMBERS DOWN BELOW, THEY'RE NOT REALLY WHOLE NUMBERS
WHAT ARE THESE?
THESE ARE THE AVERAGE ATOMIC MASS OF EACH ELEMENT.
AND THE REASON WHY THEY'RE NOT WHOLE NUMBERS
IS REMEMBER THAT WE HAVE ISOTOPES, RIGHT?
AND THE ISOTOPES OCCUR IN DIFFERENT AMOUNTS.
AND SO, THE ISOTOPES AND THEIR ABUNDANCES ARE WHAT WE USE
TO CALCULATE THESE AVERAGE ATOMIC MASSES.
AND SO, WE'LL BE LOOKING AT THAT IN THE FUTURE VIDEO,
BUT FOR NOW, WE JUST WANT TO GET OUR BEARINGS AND GET INTRODUCED
TO THE PERIODIC TABLE AND START TO RECOGNIZE
ALL THE DIFFERENT TYPES OF INFORMATION THAT IT COMMUNICATES
WITH US.
SO, NOW, LET'S HAVE A LITTLE BIT OF A WRAP-UP PAGE
TO MAKE SURE THAT WE UNDERSTAND THE MAIN POINTS OF THIS VIDEO.
SO, HERE'S OUR LAST PAGE FOR THIS VIDEO.
NOW, KEEPING THE TERMS STRAIGHT IS REALLY THE PATH TO MASTERY.
SO, WHEN WE'RE TALKING ABOUT ATOMS,
THAT'S DEFINITELY MICROSCOPIC, RIGHT?
AND IF WE'RE TALKING ABOUT ELEMENTS AND COMPOUNDS,
THAT'S MACROSCOPIC.
SO THE ATOM IS THE SMALLEST PIECE OF AN ELEMENT, RIGHT?
SO, JUST THINK BACK TO DEMOCRITUS, THE ATOMOS.
SO, IT'S OFTEN WE CAN COMMUNICATE WITH ATOMS
AND ELEMENTS KIND OF SYNONYMOUSLY,
BUT THEY REALLY ARE DIFFERENT.
AND THEN, REMEMBER THAT COMPOUNDS THEN
ARE THE FIXED RATIO OF ATOMS THAT FORM A PARTICULAR COMPOUND.
SO, THESE ARE ALL DEFINED FOR YOU HERE.
SO, LET'S MAKE SURE WE FEEL REALLY CONFIDENT ON THIS.
SO, WHEN WE LOOK AT WATER, HERE'S OUR FORMULA SUBSCRIPTS
AND WE DON'T SHOW THE ONE, IT'S UNDERSTOOD.
SO, THIS TELLING US WE HAVE TWO HYDROGEN ATOMS
TO ONE OXYGEN ATOM, RIGHT?
SO, THE RATIO OF HYDROGEN TO OXYGEN IS TWO TO ONE.
LET'S LOOK HERE.
SO, THIS IS GLUCOSE, OKAY?
SO, IF WE LOOK AT GLUCOSE...
SO, LOOKING AT THOSE FORMULA SUBSCRIPTS...
SO, WE WOULD HAVE SIX CARBON ATOMS, TWELVE HYDROGEN ATOMS,
AND SIX OXYGEN ATOMS, RIGHT?
SO, THE RATIO OF CARBON TO HYDROGEN TO OXYGEN
IS SIX TO TWELVE TO ZERO.
SO, LOOPING EVERYTHING TOGETHER THAT WE'VE LEARNED.
NOW, LET'S LOOK AT ONE MORE THING, ALL RIGHT?
SO, IF WE LOOK AT CALCIUM PHOSPHATE,
HOW MANY ELEMENTS ARE PRESENT?
SO, WE HAVE CALCIUM, PHOSPHOROUS, AND OXYGEN.
SO, THERE'S ONLY THREE ELEMENTS PRESENT,
BUT HOW MANY ATOMS, RIGHT?
SO, WE LOOK AT OUR FORMULA SUBSCRIPTS.
SO, WE HAVE THREE CALCIUMS, TREAT THIS MATHEMATICALLY,
WE HAVE TWO PHOSPHATES, SO, WE'RE GOING TO HAVE
TWO PHOSPHOROUS ATOMS.
AND THEN WE'RE GOING TO HAVE TWO OXYGENS
AND--OR, TWO SETS OF PHOSPHATES,
SO, THAT WOULD BE EIGHT ALL TOGETHER.
SO, FIVE PLUS EIGHT WOULD BE THIRTEEN.
SO, WE HAVE THREE ELEMENTS PRESENT BUT THIRTEEN ATOMS.
OKAY. WELL, THAT CONCLUDES OUR INTRODUCTION
TO ATOMIC STRUCTURE.
TAKE SOME TIME NOW TO REVIEW THESE NOTES.
MAKE SURE THEY MAKE SENSE AND WORK A FEW PRACTICE PROBLEMS
TO REINFORCE YOUR UNDERSTANDING.