ATOMIC  STRUCTURE

ATOMIC  STRUCTURE

ATOMIC MASS UNIT (a.m.u.) A system of mass measurement  used for extremely tiny particles  (such as the parts of an atom) 1 a.m.u. = 1.66 x 10-24g =  .00000000000000000000000166 g Which would you rather write?

NUCLEUS The positively charged “center” of an atom Virtually ALL of an atom’s mass is located in the nucleus Composed of protons and neutrons

PROTONS Positively charged particles that are located in the nuclei of atoms Mass = 1 atomic mass unit (a.m.u.)

NEUTRONS Uncharged particles located in the nuclei of atoms Mass = 1 a.m.u.

ELECTRONS Negatively charged particles that surround (orbit) the nuclei of atoms Electrons have virtually NO mass: Mass = 0 a.m.u.

Let’s Synthesize!

Bohr Model of Oxygen Nucleus Number of  Protons Electron Energy  Levels Number of  Neutrons

Smaller particles of matter....Quarks Scientists hypothesize that electrons are  not make up of even smaller particles,  however, protons and neutrons are! The particles are called quarks. At the present time, scientists believe that  three quarks make up a proton, and three  quarks make up a neutron.

The Tevatron The Tevatron is the most  powerful proton-antiproton  accelerator in the world. It  accelerates beams of protons  and antiprotons to 99.99999954  percent of the speed of light  around a four-mile  circumference. The two beams  collide at the centers of two  5,000-ton detectors positioned  around the beam pipe at two  different locations. The  collisions reproduce conditions  in the early universe and probe  the structure of matter at a very  small scale.

Finding the sixth quark took a team of nearly 450 scientists  several years. The collisions of protons with oppositely charged particles at  high energies were necessary to produce the sixth quark. This sixth quark is typically referred to as the "Top Quark".

ISOTOPE Atoms of the same element that  have different numbers of  neutrons

Label the diagram of the atom Label the diagram of the atom { { Click here for the answer Click here for the answer Nucleus Nucleus Protons Protons Neutrons Neutrons Electrons Electrons

The structure of an atom The structure of an atom Nucleus Nucleus Electrons Electrons { Neutrons Neutrons Protons Protons Click here to go back Click here to go back

Atomic Number equal the number of protons and determines the element’s place in the Periodic Table. Atomic Weight equals the weight of an atom compared with the weight of an atom of carbon 12. Atomic Mass or Mass Number equals the number of neutrons and protons. This number is very close to the atomic weight. Electrons are orbiting the nucleus in a specific order.

Periods and Groups on the P. T.

Read the handout "Supersize the Atom". Complete Periodic Table Practice  sheet for homework. Finish the Element Challenge  Sheet!

Protons, Neutrons and Electrons Protons and neutrons are located inside the nucleus. Electrons are located in shells or energy levels and orbit or move around the nucleus.

3 Rules to Remember! 1. # of Protons = # of Electrons P=E 2. Atomic number equals number of protons 3. Atomic mass or mass number equals number of  protons and number of neutrons

Name________________ Symbol_______________ Atom Number_________ Atom Mass___________ #of Protons___________ # of Electrons_________ # of Neutrons_________

Electron Configurations Name________________ Symbol_______________ Atom Number_________ Atom Mass___________ #of Protons___________ # of Electrons_________ # of Neutrons_________

Name________________ Symbol_______________ Atom Number_________ Atom Mass___________ #of Protons___________ # of Electrons_________ # of Neutrons_________

Pre 1980 pennies needed for  Friday. Bring 2pennies in.

WITHOUT USING A PERIODIC TABLE, COMPLETE THE FOLLOWING AND DRAW THE  ELECTRON CONFIGURATION. Name________________ Symbol_______________ Atom Number_________ Atom Mass___________ #of Protons___________ # of Electrons_________ # of Neutrons_________ Ca 20 20

G L N U F D T M A Q S P H V X J C B K Y R I O W E

Gold and Silver Pennies (or How to be an  Alchemist) Lab Safety: This lab requires safety goggles!! The strong heated base can severely damage your eyes and skin. Much caution  is required during the entire lab!! Solid sodium hydroxide or  solutions of sodium hydroxide  will cause chemical burns ,  permanent injury or scarring  if it contacts unprotected  human, or other animal,  tissue. It will cause blindness  if it contacts with the eye.  Protective equipment such as  eye protection should always  be used when handling the  material or its solutions.

Gold and Silver Pennies (or How to be an Alchemist) Lab Safety: This lab requires safety goggles!! The strong heated base can severely damage your eyes and skin. Much caution is required during the  entire lab!! Materials: Strong base solution (NaOH), zinc powder, alcohol burner and stand, 100 ml beaker, balance and weighing paper, graduated cylinder,  forceps, beaker tongs, crucible tongs, two pennies dated earlier than 1980 per  person (total 4 pennies) Procedure for Part I: Measure 25 mL of base solution in a graduated cylinder and pour it into  the beaker. Light the burner and set it under the stand. Put the beaker on the stand and start heating it. Measure 1.0 g of zinc powder on a balance, using the weighing paper  technique. Pour the zinc powder into the strong base. Put one copper penny PER PERSON into the hot base solution. Stir the pennies for 3 minutes with forceps. WARNING: Do not let the solution boil. Don’t breathe the fumes. Be careful to not spill the base solution! Remove the pennies with a forceps and rinse in cold running water for  a count of 20 seconds. Remove caked-on zinc with fingers. Set your  “silver” pennies aside.

Procedure for Part II: 1. Put one copper penny per person again into the hot base. 2. Stir the pennies again for another 3 minutes. 3. Take out the pennies and rinse in cold water again for 20 seconds. Dry the pennies, making sure the caked on zinc is gone. Use a crucible tong to  hold one penny at a time in the flame of your burner. Do this until the penny  turns “gold”. Don’t leave your pennies in the flame too long or they will not be  shiny. Each person should now also have a “gold” penny. Clean up: Wear your goggles. Pour the base solution down the sink with plenty of running water. Rinse your graduated cylinder. Wipe up your lab area. Answer the questions on the back to complete this lab.

Alloy A homogeneous mixture or solid solution of two or more metals. Examples: magnelium - magnesium and aluminum  used for making balances. brass- copper and zinc bronze- copper and tin sterling silver- copper and silver solder- tin and lead

Materials with a Past

1. What is an alloy? 2. Why is an alloy a homogeneous  mixture? 3. What is brass? 4. What is bronze? 5. Name two more alloys containing  copper. 6. What is an amalgam? 7. What do all steel alloys have in  common?

Questions: 1. What are the modern abbreviations for the above elements?  Zinc _________ Copper _______ Tin __________ Lead __________ 2. How are elements different from mixtures? ___________________________________   ___________________________________________________________________________ 3. How many different elements does it take to make a mixture? _________________ 4. Would this drawing represent an element or a mixture? _______________________ 5. How many atoms are drawn above (see C.) for each mixture?  Brass ____________ Bronze _____________ Solder ______________ 6. How many different elements does it take to make each of the alloys drawn  above? Brass  __________ Bronze __________ Solder ___________ 7. What element coats the “silver” penny you made in lab? ____________________ 8. What alloy coats the “gold” penny? ____________________________ 9. Draw an alloy of the elements zinc, copper, and tin made up of ten total atoms,  using the  Dalton Models above. 10. Sterling silver is an alloy of silver and copper. Make up a drawing of a sample of sterling  silver, using 10 atoms. (You’ll have to think of a way to represent  silver atoms first.)

An ALLOY is a mixture of metals. They are mixed  when the metals are melted together, but there is  NOT a chemical reaction between the atoms. Some  common alloys are in the table below. Alloys have  very different properties than the individual  metals that make them up.

1. How many different elements does it take to make an alloy? 2. How many elements are in the alloys… Brass? ___ Bronze? ___ Pewter?___ Stainless Steel? _____ 3. Stainless steel is what your silverware and knives are made  of. Why is the alloy stainless steel better for silverware than  pure iron? 4. What ALLOY coats the “gold” penny you made in lab? Hint-  you melted one metal into another metal.  _____________________ 5. A copper atom has ____ protons in its nucleus. It has  _____ electrons outside its nucleus. It also has ____ neutrons  in its nucleus. A copper atom’s atomic number is ______ and its  mass number is _________.

ATOMIC  STRUCTURE