Atoms and the Periodic Table of Elements February 2016

Atoms Nucleus Center of the Atom Protons and Neutrons Found Here Contains Almost ALL of the Atom’s Mass Electron Cloud Area Around the Nucleus where the Electrons are Found

Blurry Area Containing Atoms…Continued Electron Cloud Blurry Area Containing Electrons Nucleus Protons + Neutrons

Atoms…Relative Size One dust particle has millions of atoms 100 million million billion hydrogen atoms are in a regular size balloon Twenty thousand billion billion atoms are in a nickel Imagine 1 grain of rice is one electron. 2,000 grains of rice represent a proton. Imagine that an electron is as big as a grain of sand. Then the nucleus of an atom would be as big as a marble. The electron cloud would have a radius of 25 meters! If we could magnify the simplest hydrogen atom to the size of the earth, then the nucleus (a proton) would only be about the size of a basketball. It would be at the very center of the earth and that lonely electron would be found somewhere out in earth's atmosphere. All of the space in between the electron and the basketball-size nucleus is empty!

Atoms…Relative Size…Continued

Subatomic Particles Proton Positive “1” Charge Mass of “1” Found in Nucleus Determines the ELEMENT (3P = Li; 30P = Zn) Neutron Neutral or Zero Charge Electron Negative “1” Charge Very Little “0” Mass Found in Electron Cloud Surrounding Nucleus

Subatomic Particles…Continued

Atom Variations BrainPOP - IONS Isotopes Atoms of the SAME ELEMENT with a Different (+ or -) number of NEUTRONS ONLY the Atomic Mass changes Read and Written as “Carbon-14” or “Uranium-236” Ions An Atom or Molecule that has a Different Number of Electrons than Protons Adding Electrons Creates a NEGATIVE ion Subtracting Electrons Creates a POSITIVE ion BrainPOP - IONS

The Periodic Table INB page 126 - 127 Method of organization Dmitri Mendeleev 1869 Predicted the properties of elements and predicted the discovery of other elements based on the trends in the table. Based on atomic mass. Moseley discovered that a more appropriate basis was atomic number. Periodic Law—When elements are arranged in order of increasing atomic number, their physical and chemical properties show a periodic pattern.

The Periodic Table Periodic Occurring or Recurring at Regular Intervals Columns are called “Groups” Rows are called “Periods” Elements are Arranged in Many Ways on the Periodic Table Similar Properties Reactivity Atomic Size Density Etc…

Trends Size of Atoms Decreases from LEFT to RIGHT and Increases from TOP to BOTTOM Largest: Cesium Smallest: Helium

Trends…continued Density Increases from TOP to BOTTOM Increases from the OUTSIDE INWARD Hydrogen: 0.00009 g/cm3 Osmium: 22.57 g/cm3 Melting and Boiling Points decrease as you move down a group and increase as you move left to right across a period.

On Your Periodic Table, Add: Alkali Metals Noble Gases Oxygen Group Carbon Group Alkaline Earth Metals Halogens Boron Group Nitrogen Group 1 18 1 2 Transition Metals 13 14 15 16 17 2 3 4 5 6 7 8 9 3 10 11 12 4 5 6 7

Metals & Nonmetals Nonmetals (right of zig-zag line) No luster Metals (left of zig-zag line) Luster/shine Good conductors of heat and electricity. Malleable (hammered or rolled into sheets) Ductile (stretched or drawn into wires) All are solids except for Mercury Nonmetals (right of zig-zag line) No luster Poor conductors Not malleable or ductile Many are gases; Bromine is a liquid; some are solids

Metalloids Metalloids ( 7 Eelements ALONG zig-zag line) Called semi-metals Have properties of BOTH metals and nonmetals Example – Silicon Shiny Brittle Poor electrical conductor Example – Boron Acts as a metal when reacting with Fluorine Acts as a nonmetal when reacting with Sodium

Element “Boxes” Atomic Number Determines Element = Protons = Electrons Atomic Symbol 1 or 2 Letters 1st is Capitalized 2nd is NOT Atomic or Element Name Atomic Mass = Protons + Neutrons

Atomic Math! 99 # Protons = _____ (Same as Atomic Number) # Electrons = _____ (Same as Atomic Number) # Neutrons = _____ (Rounded Atomic Mass MINUS Atomic Number) 99 153 41 # Protons = ____ # Electrons = _____ # Neutrons = _____ 41 52

Group 1: Alkali Metals K 1 Valence Electron Never found in elemental form in nature Very Reactive Stored under oil Silver in Color Soft Form “Salts” with Halogens K

Group 2: Alkaline Earth Metals 2 Valence Electrons Moderately Reactive Silver in Color Soft Mg

Groups 3-12: Transition Metals All “useful” metals Random properties and electron configurations

Group 13: Boron Group 3 Valence Electrons Ga

Group 14: Carbon Group 4 Valence Electrons C

Group 15: Nitrogen Group 5 Valence Electrons Moderately Reactive Some VERY TOXIC (P, As, Sb) P

Group 16: Oxygen Group 6 Valence Electrons Moderately Reactive Te

Group 17: Halogens 7 Valence Electrons Very Reactive All form Acids with Hydrogen Forms “salts” with Alkali Metals At

Group 18: Noble Gases 8 Valence Electrons (*2 for Helium) Full Valence Shells Non Reactive (Inert) Kr

Periodic Table “QUIZ” Foldable Group / Family Name # Valence Electrons (except groups 3-12) Lewis Dot Structure – (Choose an Element in Each Group – Do NOT Do a Lewis Dot Diagram for Groups 3 - 12!) Facts Group 1: 3 Facts Group 2: 2 Facts Groups 3-12: 1 Fact Group 15: 1 Fact Group 16: 1 Fact Group 17: 2 Facts Group 18: 2 Facts