Atomic History and Atomic Structure 8th Grade Science

Do Now Monday October 17th Classify each element as a metal, nonmetal, or metalloid. Arsenic (As) Xenon (Xe) Aluminum (Al) An element that is malleable, ductile, and a good conductor of heat and electricity An element that is a a dull solid that is brittle An element that is shiny and is a semi-conductor.

TODAY’S PLAN TODAY’S DO Identify 6 scientists who contributed to our knowledge of the structure of the atom. Explain the structure of the atom. Differentiate between the subatomic particles of an atom: protons, neutrons, and electrons; TODAY’S DO Complete a WebQuest about Atomic History and Atomic Scientists (Independently and Quietly)

Do Now Tuesday October 18th What are the properties of metals? What are the properties of metalloids? What are the properties of nonmetals?

TODAY’S PLAN TODAY’S DO Identify 6 scientists who contributed to our knowledge of the structure of the atom. Explain the structure of the atom. Differentiate between the subatomic particles of an atom: protons, neutrons, and electrons. Discuss what the atomic number represents concerning the atoms of an element. Discuss what the mass number represents concerning the atoms of an element. TODAY’S DO Quiz Briefly review scientists and atomic structure Calculate the number of protons, neutrons, and electrons in atoms of an element.

Atomic Theory Changes over time…

Atomic Theory Because we can not see atoms, we use models to teach and learn about atoms. The atomic theory has changed over time as new technologies have become available. Remember: Scientific knowledge builds on past research and experimentation.

On Page 40 Make a list of these names. Skip a line or two between each one so you can write a brief statement about each. Democritus Dalton JJ Thomson Rutherford Bohr Schrodinger

Atomic Theory Timeline Scientist Information Model Democritus (400 BC) Named atoms “atomos” Said everything is composed of atoms. Atoms are indestructible. Between atoms lies empty space. There is an infinite number and kinds of atoms.

Atomic Theory Timeline Scientist Information Model John Dalton (2000 years after Democritus) All matter is made of atoms. Atoms are too small to see, indivisible and indestructible. All atoms of a given element are identical.

Atomic Theory Timeline Scientist Information Model J.J. Thomson Discovered the negative electron, using the cathode ray tube Plum Pudding model

Atomic Theory Timeline Scientist Information Model Ernest Rutherford Atoms are mostly empty space Discovered tiny, positively charged NUCLEUS using the gold-foil experiment Name positive charged particle “proton”

Atomic Theory Timeline Scientist Information Model Neils Bohr Concluded that electrons are located in neat planet-like orbits around the nucleus in certain energy levels

Scientist Information Model Schrodinger (and many others): Modern Atomic Theory Electrons do not orbit the nucleus in neat planet-like orbits but move at high speeds in an electron cloud around the nucleus. We can not know the exact location of an electron.

Rings (energy levels) outside nucleus Atomic Structure Copy this table into your journal. Subatomic Particle Mass (amu) Charge Location Proton (p+) 1 +1 nucleus Neutron (no) Electron (e-) -1 Rings (energy levels) outside nucleus

Atomic Structure

Atomic Number and Mass Number Identifies the element Is the number of protons In a neutral atom, is also the number of electrons Mass Number Decimal number rounded to nearest whole number Includes both protons and neutrons Mass number = p+ + no So, no = mass number – p+ Mass number when rounded

Calculating protons, neutrons, electrons p+ = atomic # = 1 e- = p+ = 1 no = mass # - atomic # = 1-1 = 0

Calculating protons, neutrons, electrons p+ = atomic # = 2 e- = p+ = 2 no = mass # - atomic # = 4-2 = 2

Calculating protons, neutrons, electrons p+ = atomic # = 3 e- = p+ = 3 no = mass # - atomic # = 7-3 = 4

Do Now Wednesday October 18th Answer the questions on the sheet given to you. Blood Types of 100 Donors

TODAY’S DO TODAY’S PLAN Determine the electronic structure for elements 1-20 on the Periodic Table. TODAY’S DO Check Homework Review calculating the number of protons, neutrons, and electrons. Draw the electronic structure of elements.

Element Symbol p+ e- n0 1st energy level 2nd energy level 3rd energy level 4th energy level Hydrogen Helium Lithium Beryllium Carbon Nitrogen Oxygen Fluorine Sodium

Element Symbol p+ e- n0 1st energy level 2nd energy level 3rd energy level 4th energy level Magnesium Aluminum Silicon Phosphorus Chlorine Argon Potassium Calcium

Electronic Structure E1 = 2 electrons E2 = 8 electrons

Electronic Structure Example

Electronic Structure Example

Electronic Structure example

Do Now Friday October 20th TURN IN YOUR HOMEWORK SHEET FROM WEDNESDAY IN THE BLACK BASKET. Pick up from the front table and answer the questions on the sheet given to you. Once you have finished, raise your hand so I can check your work. Only when you have shown me that you know how to do the work will you be allowed to construct your model of an atom.

TODAY’S DO TODAY’S PLAN Explain the structure of the atom. Discuss what the atomic number represents concerning the atoms of an element. Discuss what the mass number represents concerning the atoms of an element. Determine the electronic structure for elements 1-20 on the Periodic Table. TODAY’S DO Create Bohr Model of an atom of an assigned element

Do Now Tuesday October 25th Draw and complete the table. Atomic Symbol Atomic Number Protons Neutrons Electrons Mass Number Al 6 Draw the electronic structure for Al.

TODAY’S DO TODAY’S PLAN Create a Bohr Model of an atom. Discuss what the atomic number represents concerning the atoms of an element. Discuss what the mass number represents concerning the atoms of an element. TODAY’S DO Create/Finish your Bohr Model of an atom of an assigned element When finished with your atom model, pick up a puzzle sheet from the table in the front of the room and practice calculating protons, neutrons, and electrons for elements. Color your sheet (with pencil) as directed to solve the puzzle. Calculating p+, n0, e- QUIZ TOMORROW, Wednesday, October 26th!!

Bohr Atomic model Beads: electrons, protons, and neutrons (3 different colors) Pipe cleaners: energy levels Make a nucleus by stringing the correct number and color of beads onto 1 pipe cleaner. The smash it into a little ball. Make the appropriate number of energy levels by using 1 (for smaller energy levels) or 2 (larger energy levels) pipe cleaners with the correct color and number of beads for each energy level. Connect the nucleus and each energy level by attaching strings between each so that all can spin freely. (Nucleus and energy levels should not touch.) Attach the card for your element to the bottom of your model and hang from a cabinet or the line in the back of the room.