ATOMS AND ATOMIC THEORY PERIODIC TABLE AND ITS PROPERTIES CHEMICAL BONDS

THE ATOM -The smallest piece of matter that still retains the property of the element.

THE ATOM AND ITS PARTS NUCLEUS ELECTRON CLOUD E E P N E ELECTRON (-) NEUTRONS (no charge) ENERGY LEVEL PROTONS (+)

QUARKS = particles that make up protons and neutrons -Quarks are held together by nuclear forces -6 Quarks = Proton -3 Quarks = Neutron -How do they know this? -Look at picture on pg. 508

IDENTIFYING ATOMS ATOMIC NUMBER -# of protons 6 -# of electrons -Tells you what type of atom you have 6 Carbon C 12 ATOMIC MASS -# of protons + # of neutrons -AMU = atomic mass unit = unit of measurement # of Neutrons = mass # - atomic #

BOHR MODELS and ELECTRON DOT DIAGRAMS -Show how electrons are arranged in energy levels. -Use: 2n2 -Use: Atomic # Stable Atoms: -Have 2 e if they only have 1 shell -Have 8 e if they have more than 1 shell e P/N e Na Cl Electron-dot diagrams use the elements symbol and dots to show the # of electrons in the outer level

EVOLUTION OF THE ATOMIC MODEL Famous Dead Guy = Democritus Time Period = 400 BC Experiment = None/Philosopher in Greece – He reasoned that all substances were made up of ATOMS Results = Atoms were solids that couldn’t be subdivided = “UNCUTTABLE” ATOM

EVOLUTION OF THE ATOMIC MODEL Famous Dead Guy = John Dalton Time Period = 1800s Experiment = Wanted to explain how and why elements combine together in fixed ratios, so he developed a theory Results = Theory states: Each element has its own atoms which can rearrange/recombine with other atoms in chemical reactions. Idea of the atom = SOLID SPHERE

EVOLUTION OF THE ATOMIC MODEL Famous Dead Guy = John Thomson Time Period = 1904 Experiment = Used cathode-ray tubes with beams of electrons inside. The electrons were attracted to positive charges within the tube. Results = The atom was a ball of positive charges with small negative particles called electrons **DISCOVERED THE ELECTRON*** Model of the atom = PLUM PUDDING MODEL

EVOLUTION OF THE ATOMIC MODEL Famous Dead Guy: Ernest Rutherford Time Period: 1911 Experiment:Shot alpha particles (positive charges) through Gold Foil. Some passed straight thru, others bounced off at angles Results: Said the atom had a small core of positive charge surrounded by electrons

EVOLUTION OF THE ATOMIC MODEL Famous Dead Guy: Niels Bohr Time Period: 1913 Experiment: Noticed that each element had its own line spectra (light).This meant atoms could give off energy. Results: Electrons exist on energy levels. When they get excited, the jump up a level and emit light.

EVOLUTION OF THE ATOMIC MODEL - Electron Cloud Model = Current = ELECTRON CLOUD = electrons don’t travel on orbitals. Electrons are found in the electron cloud = area around nucleus where electrons are most likely found. Each level of an atom can only hold a specific amount of electrons: 2n2 1st level: n=1: 2(1)2 = 2 electrons 2nd level: n=2: 2(2)2 = 8 electrons 3rd level: n=3: 2(3)2 = 18 electrons 4th level: n=4: 2(4)2 = 32 electrons

THE PERIODIC TABLE -Periodic = “Repeated in a pattern” -Ex: phases of the moon, days of the week, calendars -Periodic Table = way to organize the elements using patterns -Developed by: Dmitri Mendeleev in the late 1800s -Arranged in order of INCREASING ATOMIC # and by CHANGES IN PHYSICAL AND CHEMICAL PROPERTIES -ATOMIC # always INCREASES from LEFT to RIGHT -As you go from the left to the right, one proton and one electron are added to each element!

THE PERIODIC TABLE GROUPS: vertical columns -AKA: FAMILIES -# 1-18 -Elements in each group have SIMILAR PROPERTIES -Ex: Group II = shiny metals, good conductors -Elements in the same group have THE SAME # OF ELECTRONS in their OUTTER ENERGY LEVEL -This determines the CHEMICAL PROPERTIES of the element

THE PERIODIC TABLE PERIODS: horizontal rows -Increase by one proton and one electron as you go left-right METALS: On the left side of the table up to the metalloids METALLOIDS: “Semimetals” - have properties of metals and nonmetals. -Form a downward staircase NONMETALS: On the right side of the table -Also includes Hydrogen (found on the left) SYMBOLS: 1-2 letter abreviation of the element

GENERAL TRENDS IN THE PERIODIC TABLE ADD TO YOUR PERIODIC TABLE!! -Electronegativity: An atom’s desire to GRAB another atom’s electrons -Periods: It INCREASES from LEFT TO RIGHT -why?? -Groups: It DECREASES as you GO DOWN a group

GENERAL TRENDS IN THE PERIODIC TABLE Ionization Energy: Amount of ENERGY required to REMOVE the outermost ELECTRON RELATED TO ELECTRONEGATIVITY Periods: INCREASES from the LEFT to the RIGHT Why? Groups: DECREASES as you go DOWN a group

GENERAL TRENDS IN THE PERIODIC TABLE -Reactivity: How LIKELY/vigorously an atom is to REACT with other substances -Determined by how easily electrons can be removed (ionization energy) and how badly an atom wants to take other atom’s electrons away (electronegativity) -Metals: -Periods: DECREASES from LEFT to RIGHT -Groups: INCREASES as you go DOWN -Nonmetals: -Periods: INCREASES from LEFT to RIGHT -Groups: DECREASES as you go DOWN

GENERAL TRENDS IN THE PERIODIC TABLE -Melting Point: -METALS: DECREASES as you go DOWN -NONMEALS: INCREASES as you go DOWN

PROPERTIES OF METALS Malleable = they can be HAMMERED into THIN SHEETS Ductile = they can be DRAWN into WIRES Most are HARD, SHINY SOLIDS GOOD CONDUCTORS of electricity -Ex: Copper, Gold, Silver -Some are MAGNETIC -Ex: Cobalt, Nickel, Iron

METAL FAMILIES 1. ALKALI METALS (Group 1) -1 valence electron (in their outer shell) -Highly Reactive (want to give away their one electron to become full and stable) -Shiny, Malleable, and Ductile -Good Conductors -Never found alone in nature because they are the most reactive metal

METAL FAMILIES 2. ALKALINE EARTH METALS (Group 2) -2 valence electrons -Very Reactive (want to give away their 2 electrons to become full and stable) -Shiny, Malleable, and Ductile -Never found alone in nature)

METAL FAMILIES 3. Transition Metals (Groups 3B - 12B) -1, 2, or 3 valence electrons -Less Reactive than groups 1 and 2 -Some are MAGNETIC (Iron, Nickel, and Cobalt) -Some are very good CONDUCTORS (Copper, Gold) -MERCURY is the ONLY LIQUID METAL

METAL FAMILIES 4. Synthetic Elements (Manmade) -Most are in Periods 6 and 7 -11 are in the ACTINOID and LANTHANOID series -RADIOACTIVE

PROPERTIES OF NONMETALS -GROUPS 7A AND 8A -SOLIDS, LIQUIDS, or GASES at room temp. -DULL in color -VERY BRITTLE -POOR CONDUCTORS

NONMETAL FAMILIES 1. Hydrogen -1 electron, 1 proton, 0 neutrons -HIGHLY REACTIVE (the Hindenburg??) -Very LIGHT -FLAMMABLE -Makes up 90% of all atoms in the universe

NONMETAL FAMILIES 2. Halogens (Group 7A or 17) -7 valence electrons -HIGHLY REACTIVE (want to steal 1 electron to be full/stable) -Salt Formers (ex. NaCl) -MOST REACTIVE NONMETALS

NONMETAL FAMILIES 3. Noble Gases (Group 8A or 18) -Complete outer shell -Helium has 2 on the 1st shell = full -The rest all have 8 = full -DO NOT FORM COMPOUNDS (b/c they’re stable)

METALS, NONMETALS, METALLOIDS MIXED GROUPS: METALS, NONMETALS, METALLOIDS GROUPS 13-16 (3A-6A) 1. Boron Group (Group 3A or 13) -3 valence electrons -A few are SEMICONDUCTORS

METALS, NONMETALS, METALLOIDS MIXED GROUPS: METALS, NONMETALS, METALLOIDS GROUPS 13-16 (3A-6A) 2. Carbon Group (Group 4A or 14) -4 valence electrons -Carbon = nonmetal -Silicon/Germanium = metalloids -Tin/Lead = metals

METALS, NONMETALS, METALLOIDS MIXED GROUPS: METALS, NONMETALS, METALLOIDS GROUPS 13-16 (3A-6A) 3. Nitrogen Group (Group 5A or 15) -5 valence electrons -Nitrogen = 78% of our atmosphere -N/P/As = nonmetals -Sb = metalloid -Bi = metal

METALS, NONMETALS, METALLOIDS MIXED GROUPS: METALS, NONMETALS, METALLOIDS GROUPS 13-16 (3A-6A) 4. Oxygen Group (Group 6A or 16) -6 valence electrons -Oxygen = 21% of our atmosphere -O/S/Se = nonmetals -Te/Po = metalloids

ISOTOPES Isotope = Atoms of the same element that have different numbers of neutrons ex: Carbon-12 = nonradioactive (6 P and 6 N) Carbon-14 = radioactive (6 P and 8 N) Atomic Mass v/s Average Atomic Mass - Atomic mass = protons + neutrons in a single atom - Average Atomic mass = average mass of the mixture of an element’s isotopes