Unit ThreeElements and the Periodic Table

Ca

B

Be

Zn

Ti

Au

THE ATOM 

The smallest part of an element that has

properties of that element.

In 1981, a type of microscope called a scanning tunneling microscope (STM) was developed.

Photo courtesy National Institute of Standards and Technology (NIST)

<http://www.howstuffworks.com/framed.htm?

parent=atom.htm&url=http://nist.gov>

STM image of a single zigzag chain of cesium atoms (red) on a gallium-arsenside surface (blue)

Copperatoms

nanotechweb.org/articles/news/3/9/8/1/niststm1

MODEL

A way scientists explain something unknown by relating it to something

that can be seen or understood.

What are some reasons scientists use models?

You have certainly had experience with models in science in your past. Name one of the models you have used in science class.

Model of an atom.

Why is our current understanding of the atom still considered a model or a theory?

Empedocles (49- 432 BCE) argued that all matter was composed of four elements: fire, air, water, and earth. The ratio of these four elements affected the properties of the matter.

Atomic Model Timeline

Democritus2500 years agoFirst idea of an atom"atomos" (invisible)

He suggested that atomos were eternal and could not be destroyed.

Democritus theorized that atomos were specific to the material that they made up, meaning that the atomos of stone were unique to stone and different from the atomos of other materials, such as fur.

This was a remarkable theory that attempted to explain the whole physical world in terms of a small number of ideas.

Democritus

Middle Ages, 1200-1600

Goal was to change cheap elements into gold

Philosopher’s Stone

 Alchemy

The philosophers' stone is a legendary alchemical substance, said to be capable of turning base metals , especially lead , into gold; it was also sometimes believed to be an elixir of life , useful for rejuvenation and possibly for achieving immortality .

The Scientific Revolution1600-1700’s

 Copernicus-the Sun  is the center of the   Solar System.

Galileo-advanced telescopes & experimental physics Newton-

Laws of Motion & Gravity

John Dalton

early 1800’s

“Father of theAtomic Theory”

John Dalton

School Teacher from England

19th Century (1807)

He combined the idea of elements with the Greek theory of atoms.

Dalton’s Atomic Theory

All matter is made of atoms

Atoms can’t be created or destroyed

All atoms of one element are the same

Atoms of different elements can combine to form new substances

John Dalton pictured the atom as a hard sphere with the same makeup throughout the entire atom.

William Crookes

English Scientist 1870'sTested Dalton's theory of the atom.

Experimented with an airless glass tube with two metal pieces hooked to a battery.

Cathode ray tube + CRTSame type of mechanism found in tv's and computer monitors

Saw a "beam" of something from the negatively charged cathode to the positively charged anode.

The beam looked like a grennish-yellowish light, but Crookes said it was a beam of particles.

He couldn't prove it!!! (bummmer!)

J. J. Thomson

1897 English physicist

Worked on Crooke's experiments. Use a magnet next to the glass tube.

Proved that the beam was not light...Light can not be bent with a magnet.The beam bent towards the magnet.....Opposite charges attract.Knew that the particles were negatively charged. HOW?

Named the negatively charged particles ELECTRONS.

J J Thomson's model of the atom.

"Plum Pudding Model of the Atom"

Your assignment: write in the symbols for each of the elements, and learn them.

Quiz on the elements will be next week.

Element Name Symbol Aluminum _____ Antimony _____ Argon _____  Arsenic _____ Barium _____ Beryllium _____ Bismuth _____ Boron _____ Bromine _____ Calcium _____ Carbon _____ Chlorine _____ Chromium _____ Cobalt _____ Copper _____ Fluorine _____ Gallium _____ Germanium _____ Gold _____ Helium _____ Hydrogen _____ Iodine _____ Iron _____ Krypton _____ Lead _____ 

Element Name SymbolLithium _____ Magnesium _____ Manganese _____ Mercury _____ Neon _____ Nickel _____ Nitrogen _____ Oxygen _____ Phosphorus _____ Platinum _____ Plutonium _____ Potassium _____ Radon _____ Selenium _____ Scandium _____ Silicon _____ Silver _____ Sodium _____ Sulfur _____ Tin _____ Titanium _____ Tungsten _____ Uranium _____ Vanadium _____ Zinc _____ 

Element Name Symbol Aluminum Al Antimony Sb Argon Ar  Arsenic As Barium BaBeryllium Be Bismuth Bi Boron B Bromine Br Calcium Ca Carbon C Chlorine Cl Chromium Cr Cobalt CoCopper CuFluorine F Gallium Ga Germanium Ge Gold Au Helium HeHydrogen H Iodine IIron Fe Krypton Kr Lead Pb 

Element Name SymbolLithium Li Magnesium Mg Manganese Mn Mercury Hg Neon Ne Nickel Ni Nitrogen N Oxygen O Phosphorus P Platinum PtPlutonium Pu Potassium K Radon Rn Selenium Se Scandium Sc Silicon Si Silver Ag Sodium Na Sulfur S Tin Sn Titanium Ti Tungsten W Uranium U Vanadium V Zinc Zn 

Ernest Rutherford

1906 considered the father of nuclear physics

Won the 1908 Nobel Prize in Chemistry

Wanted to see if Thomson's model of the atom was correct......

Set up an experiment that fired fast moving positively charged bits of matter (alpha particles) at a thin piece of a metal such as gold.

Alpha partices come from unstable atoms. They are positively charged, and so they are repelled by particles of matter which have a positive charge (opposites attract, like repell).

Rutherford hypothesized that the gold film did not contain enough matter to stop the speeding alpha particle or change its path...........

The unexpected results of the experiment caused Rutherford to realize that Thomson's model was incorrect, and he proposed his own model.

Rutherford's model included a nucleus in the atom.

The positively charged proton is located in the very small space at the center of an atom.

Most of the atom is empty space occupied by nearly massless electrons.

Electrically neutral particles, neutrons are also located in the nucleus.

The number of electrons equal the number of protons in an atom.

Neils Bohr  1913Electrons are in energy levels

Erwin Schrodinger1926Electron Cloud Modelelectron orbitals  have shapes

Discovered the neutron

JamesChadwick 1932

Atomic Energy - The secrets of the atom’s

nucleus is unveiled

Nuclear Power First atomic bomb-1945

From 1945 attention was given to harnessing this energy in a controlled fashion for naval propulsion and for making electricity.

Since 1956 the prime focus has been on the technological evolution of reliable nuclear power plants.

Uranium was discovered in 1789 by Martin Klaproth, a German chemist, and named after the planet Uranus.

The science of atomic radiation, atomic change and nuclear fission was developed from 1895 to 1945, much of it in the last six of those years.

Over 1939-45, most development was focused on the atomic bomb.

Hints for Learning the Element SymbolsAu - Aey U ! Give me my gold ! -or- Autumn leaves turn to gold.

Na - Na, I don’t want sodium on my food. (think of salt, NaCl)

Ag - Aged people have hair of silver.

Fe - Females need iron.

Hg - The planet Mercury is huge.

Pb - Plumbers use lead pipes.

Cu - C U (see you) later, copper !

Sn – Cut tin with tin-snips.

Pu – P U ! Plutonium stinks.

Sb – Antimony is so bad for you.

The symbol is the first two letters of the element name.Al  AluminumAr  ArgonBa  BariumBe BerylliumBi BismuthBr BromineCa CalciumCo CoboltGa GalliumGe GermaniumHe HeliumKr KryptonLi LithiumNe NeonNi NickelSc SeleniumSc ScandiumSi SiliconTi  Titanium

The element symbol is only the first letter of the element name.B BoronC CarbonF FluorineH HydrogenI IodineN NitrogenO OxygenP PhosphorousS SulfurU UraniumV Vanadium

The symbol is the first letter of the element name plus one other letter in that name.

Cl ChlorineCr ChromiumAs ArsenicMg MagnesiumMn ManganesePt PlatinumPu PlutoniumRn RadonZn  Zinc

The symbol is from a foreign word for that element, usually Greek or Latin.Sb AntimonyAu GoldAg SilverK PotassiumHg MercuryNa SodiumW TungstenSn TinPb LeadFe  IronCu Copper

BoronFluorineChlorineSodium

SulfurLithiumMercury 

IodineRadonSilver Aluminum Lead

Bariium Bromine

PlutoniumCalciumCoblt

Fluorine HeliumKryptonIron

ChlorineSilicon TinNikel

NeonZincPalladium

Copper Sodium Magnesium Argon Radium  BerylliumGold

Li Ne C O HHe

Au

AlP AgPu

CaBr

Rn

MgRaBeHgLiSSn

NBa

FKSi

Sr

Cu 

HeKrClPb

OsCo

Fe

Element symbol test tomorrow!Use your flash cards and

be ready for it!!

Welcome Mr. Koy!

Hydrogen peroxide is an oxidizer commonly used as a bleach. It is a clear liquid , slightly more viscous than water, that appears colorless in dilute solution.

It is used as a disinfectant , antiseptic , oxidizer, and in rocketry as a propellant. The oxidizing capacity of hydrogen peroxide is so strong that it is considered a highly reactive oxygen species .

What is hydrogen peroxide?What is the chemical forumla for it?

H2O2

Lab: Observing the element OXYGEN Hour ___________ Date __________

Objective: To collect and observe a sample of oxygen.

Materials: Safety glasses, 2 standard test tubes, test tube rack, 3 wood splints, manganese dioxide (MnO2), distilled water (H2O), hydrogen peroxide (H2O2), matches, graduated cylinder (10 mL), test tube clamp

Procedure:Use CLEAN, DRY test tubes. With a pencil, mark one tube “w” for water. Mark the other tube “h” for hydrogen peroxide.

Put 7 mL distilled water in the tube marked “w”. Put 7 mL hydrogen peroxide in the test tube marked “h”.

Substance State of matter

Color Observable differences?

Water

Hydrogen Peroxide

3. Complete the table below.

Substance Observations when mixed with MnO2

Water

Hydrogen Peroxide

4. Use a wooden splint to add the manganese dioxide to each of the two test tubes. Put in 1 splint-full. Record your observations below.

5. Use a new wood splint. Light the splint with a match. Let the splint burn 3 seconds, then blow out the flame. A small area on the splint will continue to glow orange. Move the glowing splint down into the tube marked “w,” but DO NOT let it touch the liquid. This is called a splint test. Observe and record below.

6. Add one more splint-full of manganese dioxide to the “h” tube. Put your thumb over the test tube and shake gently. Repeat the splint test procedure on this tube. Observe any differences in the glowing splint carefully. Record below.

Substance Splint test observations

Formula Model/Drawing

Water

Hydrogen Peroxide

QUESTIONS TO ANSWER

Look at the formulae for water and hydrogen peroxide. What elements are in each of these compounds? __________________________ and _______________________________

Which substance, water or hydrogen peroxide, has more oxygen atoms? ___________________

Oxygen is the gas that bubbled out of the tube with hydrogen peroxide. Write two properties of oxygen. ____________________________________ ______________________________________

The air we breathe contains about 19% oxygen, 79% nitrogen, and 2% carbon dioxide. Is air a MIXTURE or an ELEMENT? __________________________________

Oxygen is one of those elements sometimes confused when students write chemical symbols. Using a lower case letter for the second letter of an element’s abbreviation or symbol is important. Write the element or elements shown by each of the symbols below.

Co _______________________________C O _____________________ ________________________P O _____________________ ________________________Pu _______________________________P U _____________________ _______________________S I ______________________ _______________________Si _______________________________Ni _______________________________N I _____________________ _______________________C U ____________________ _______________________Cu ______________________________

Please use a complete sentence to explain one thing you learned by doing this lab today.____________________________________________________________________________________________________________________________________________________________ ________________________________________________