Introduction to Atoms Section 1 page

Some videos… ueCHiQhttp:// ueCHiQ You might be giants - Elements

History of Atomic Models Democritus (~400BC) –atomos = small, solid, indestructible particles of different shapes & sizes –These were just ideas, not truly science… Dalton’s Atomic Theory (1803) –Billiard Ball Model - small solid sphere –Developed notion of conservation of mass and that atoms combine in specific ratios

History of Atomic Models J.J. Thomson (1904) –Plum Pudding Model - positive and negative particles dispersed throughout the atom

Rutherford –Nuclear Model (1910) –Discovered dense positively charged nucleus of the atom while working with alpha particles Gold Foil Experiment

History of Atomic Models Neils Bohr – (1913) –Also Solar System Model –Electrons travel in specific, circular orbits Schrodinger & Heisenburg – (1926) –Quantum Mechanical Model –Dense nucleus w/ protons & neutrons –Electrons exist in ‘clouds’ called orbitals w/ specific energy levels

Atomic Theory TIMELINE Create a timeline showing the development of the atomic theory Include the following - Dates - Events - Names - Illustration for each date

ATOMS An atom has three parts: Particles ChargesLocation Proton = positive(+)center of nucleus Neutron = no chargecenter of nucleus Electron = negative (-)orbit the nucleus Smallest unit of matter

10/1/2013 Atoms QUIZ 1 (10 points) ParticlesChargeLocation Protons 1.______2._______ 3._______no chargenucleus Electrons 4. ________5._______

The Atoms Family was created by Kathleen Crawford, 1994 Presentation developed by Tracy Trimpe, 2006,

Atomic number equals the number of ____________ or ________________. Atomic mass equals the number of ______________ + _______________. The Atoms Family - Atomic Math Challenge Atomic Number Symbol Name Atomic Mass protons electrons protons neutrons To find the total of neutrons Subtract atomic # from mass # Example: Aluminum 13 protons = 14 neutrons

Assignment: Finish the rest of the worksheet and turn it in to your teacher.

10/2/2013 Atoms QUIZ 2 (10 points) 9 F Fluorine __________ Atomic # 2.__________ Mass 3.__________ # of protons 4.__________# Neutrons 5.__________# Electrons

Bohr Diagrams Find out which period (row) your element is in. Elements in the 1 st period have one energy level. Elements in the 2 nd period have two energy levels, and so on.

Nucleus 1 st shell 2 nd shell 3 rd shell

Bohr Diagrams 1)Draw a nucleus with the element symbol inside. 2)Carbon is in the 2 nd period, so it has two energy levels, or shells. 3)Draw the shells around the nucleus. C C

Bohr Diagrams 1)Add the electrons. 2)Carbon has 6 electrons. 3)The first shell can only hold 2 electrons. C C

Bohr Diagrams 1)Since you have 2 electrons already drawn, you need to add 4 more. 2)These go in the 2 nd shell. 3)Add one at a time - starting on the right side and going counter clock-wise. C C

Bohr Diagrams 1)Check your work. 2)You should have 6 total electrons for Carbon. 3)Only two electrons can fit in the 1 st shell. 4)The 2 nd shell can hold up to 8 electrons. 5)The 3 rd shell can hold 18, but the elements in the first few periods only use 8 electrons. C C

Bohr Diagrams Try the following elements on your own: a)H b)He c)O d)Al e)Ne f)K C C

10/3/2013 Bohr Model Quiz 3 (10 points) 5 B Boron Create a Bohr Model for the following elements: Protons = BLUE Electrons=RED Neutron= GREEN 10 Ne Neon

Organization of Elements and Families

Periods on the Periodic Table Horizontal rows that consist of different elements From left to right the prosperities change in patterns –Left = highly active –Middle = less active – Right= less active

Families on the Periodic Table Elements on the periodic table can be grouped into FAMILIES bases on their chemical properties. Each family has a specific name to differentiate it from the other families in the periodic table. Elements in each family react differently with other elements.

ALKALI METALS Brown) Group 1 Elements: -Lithium -Rubidium -Sodium -Cesium -Potassium -Francium Silvery Solids Low Densities Low Melting Points Hydrogen is NOT a member, it is a non-metal

ALKALINE EARTH METALS (dark Green) The Group 2 Elements -Beryllium -Magnesium -Calcium -Strontium -Barium -Radium Higher melting points than Alkali Metals Reactive, but less than Alkali metals Conduct electricity

TRANSITION METALS (Light Blue) Groups 3-12 in the middle Good conductors of heat and electricity. Some are used for jewelry. Can bond with many elements in a variety of shapes.

BORON FAMILY (Red) Group 13 Elements -Boron -Aluminum -Gallium -Indium -Thallium All are metals except Boron Aluminum is the most common metal in the Earth’s crust.

CARBON FAMILY (Yellow) Group 14 Elements -Carbon -Silicon -Germanium -Tin -Lead Silicon is used to make semiconductors for computers and other electronics. Diamond and Graphite are two forms of carbon. Group 14 Contains metals, metalloids, and a non-metal Carbon (C)

NITROGEN FAMILY (Bright green) Group 15 Elements - Nitrogen -Phosphorus -Arsenic -Antimony -Bismuth Almost 80% of the air we breathe is nitrogen. Phosphorus is an essential ingredient in healthy teeth and bones.

OXYGEN FAMILY (Navy) Group 16 Elements -Oxygen -Sulfur -Selenium -Tellurium -Polonium About 20% of the Earth’s atmosphere is oxygen. Sulfuric acid is one the most used chemicals in the world

Halogens (orange) Group 17 7 electrons in the outer shell All are non- metals Very reactive are often bonded with elements from Group 1

Noble Gases (pink) Group 18 Elements -Helium -Neon -Argon -Krypton -Xenon -Radon Helium is used to fill balloons. Neon signs contain noble gases.

Rare Earth Metals (purple) Some are Radioactive The rare earths are silver, silvery-white, or gray metals. Conduct electricity