Atoms and the Periodic Table of Elements

1. Atoms and the Periodic Table of Elements January, 2012

2. 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

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

4. 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!

5. Atoms…Relative Size…Continued

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

7. Subatomic Particles…Continued

8. Atom Variations • 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

10. The Periodic Table • 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.

11. 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…

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

13. 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.

14. 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 11 12 10 4 5 6 7

15. 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 Metals & Nonmetals

16. 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

17. 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

18. 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

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

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

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

22. Group 13: Boron Group • 3 Valence Electrons Ga

23. Group 14: Carbon Group • 4 Valence Electrons C

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

25. Group 16: Oxygen Group • 6 Valence Electrons • Moderately Reactive Te

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

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

28. “QUIZ” (Extra Flap in Flip Book) Study Information for Each Group! • Name • # Valence Electrons (except groups 3-12) • Lewis Dot Structure (Element Symbol is Given) • 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