Atomic Structure and the Periodic Table Lesson 2

1. Atomic Structure and the Periodic Table Lesson 2 August 12 & 13, 2013 Boon Chemistry

2. Catalyst • Mystery Elements! Use your periodic table and the clues below to determine the identity of 3 mystery elements. Write your answers on your white board. • This element, with a mass number of 207, is poisonous. • This element, made of atoms with 78 electrons in the neutral state, is a very expensive metal. • This element, made of atoms with 16 protons, is a gas that smells like rotten eggs. If you finish early, begin correcting your lab.

3. 1. Answer: Lead Atomic Symbol: Pb Atomic Number: 82 Mass Number: 207.2 207Pb

4. 2. Answer: Platinum Atomic Symbol: Pt Atomic Number: 78 Mass Number: 195.08 195Pt

5. 3. Answer: Sulfur Atomic Symbol: S Atomic Number: 16 Mass Number: 32.07 32S

6. Objective • When given data and a periodic table, students relate the numbers of subatomic particles in an atom and the periodic table by drawing models of atoms and distinguishing between diagrams of different isotopes and ions. More simply: I can identify an element based on its atomic structure and I can draw a model of an atom of a specific element using information found on the periodic table.

7. Writing & Reading Nuclear Symbols Format on a worksheet or lab report Format on the Periodic Table Mass Number Ion with 2+ charge Atomic Number

8. White Board Practice Write the nuclear symbol for… • Calcium-41 (mass number = 41) • Magnesium ion with 2+ charge • Argon-40 • Tungsten-184 • A gold atom with 117 neutrons • A lithium atom with 2 electrons

9. Sometimes, atoms of the same element have different numbers of neutrons. Atoms of the same element with different numbers of neutrons are called isotopes.

10. Question 1 • Three isotopes of magnesium are • Magnesium – 24 (24Mg) • Magnesium – 25 (25Mg) • Magnesium – 23 (23Mg) • Complete the Chart: • Hint! Mass number = protons + neutrons

11. Question 2 • Three isotopes of uranium are • Uranium – 235 (235U) • Uranium – 238 (238U) • Uranium – 236 (236U) • Complete the Chart: • Hint! Mass number = protons + neutrons

12. Ions are atoms with a net charge. The ion is charged because there are an unequal number of protons and electrons. • The charge is shown on the right side of the symbol: • Ex: Mg with 12 protons and 10 electrons Mg2+

13. Positive or Negative? • Positively charged ions have more protons than electrons • Ex: Ca2+ (calcium ion) has 20 protons and 18 electrons • 20 – 18 = +2 • Negatively charged ions have more electrons than protons • Ex: Br- (bromine ion) has 35 protons and 36 electrons • 35 – 36 = -1

14. Name that ion! • Sample: • 19 protons, 20 neutrons, 18 electrons • Answer: K1+ +19 p + (-18 e) = +1 • Now you try: • 13 protons, 14 neutrons, 10 electrons • 1 proton and no electrons • 53 protons, 73 neutrons, 54 electrons • 16 protons, 16 neutrons, 18 electrons • 4 protons, 5 neutrons, 2 electrons

15. Note on the Periodic Table • “groups” are columns • “periods” are rows

16. Just like you and your family share similarities… So do elements! • 3 main groups • Metals • Non-metals • Semi-metals

17. 1. METALS LOCATION on the Periodic Table: To the left, to the left…

18. 2. NON-METALS LOCATION on the Periodic Table: To the right, and with the exception of Hydrogen!

19. 3. SEMI-METALS (Metalloids) LOCATION on the Periodic Table: the Semi-metal “Staircase” What are the semi-metals? B, Si, Ge, As, Sb, Te

20. Please color-code your periodic tables. • The majority of elements are… METALS

21. B Si As Ge Sb Te

22. Things you should know about periodic table groups: • Where is the group located on the periodic table? • What groups (columns) and periods (rows) are included? • What are some of the elements included? • Are you part of the metals, semi-metals (metalloids), or non-metals? • How many valence electrons does each element possess? • Please present two more facts or examples from the textbook. (Pages 125-129 in textbook).

23. Video Review • Study Jam - atoms: http://studyjams.scholastic.com/studyjams/jams/science/matter/atoms.htm • Study Jam - Periodic table: http://studyjams.scholastic.com/studyjams/jams/science/matter/periodic-table.htm • Just How Small is an Atom? http://www.youtube.com/watch?v=yQP4UJhNn0I • Solving the puzzle of the periodic table http://www.youtube.com/watch?v=O-48znAg7VE&list=PLJicmE8fK0EjGmPGeh_WDu69qAsN-iHVA • The genius of Mendeleev’s Periodic table http://www.youtube.com/watch?v=fPnwBITSmgU&list=PLJicmE8fK0EjGmPGeh_WDu69qAsN-iHVA

24. Videos – Elements • Halogens: http://www.youtube.com/watch?v=u2ogMUDBaf4 • Alkali Metals: http://www.youtube.com/watch?v=uixxJtJPVXk • Alkaline Earth Metals: http://www.youtube.com/watch?v=B2ZPrg9IVEo

25. Detailed Notes on Periodic Table Groups Check these notes against your periodic table graphic organizer.

26. Within the 3 major groupings of elements (metals, semi-metals, non-metals), there are more SPECIFIC groups that share properties. • The elements share properties because they have the same number of VALENCE ELECTRONS.

27. VALENCE electrons: electrons that are in the OUTERMOST shell of an atom. They are the electrons available for CHEMICAL BONDING.

28. Group 1: The Alkali Metals • Have ONE valence electron. • VERY REACTIVE • Therefore, not found alone in nature. • What are the alkali metals? • Li, Na, K, Rb, Cs, Fr

29. Group 2: The Alkaline Earth Metals • Have TWO valence electrons. • VERY REACTIVE • Usually not alone uncombined in nature. • What are the Alkaline Earth Metals? Be, Mg, Ca, Sr, Ba, Ra

30. Groups 3-12: Transition metals • Properties vary. • Some found alone in nature: Gold, Silver, Platinum, Copper, etc.

31. Group 17: Halogens • Have SEVEN valence electrons. • Most REACTIVE non-metals. • What are the Halogens? F, Cl, Br, I, At

32. Group 18: The Noble Gases • Have EIGHT valence electrons. • They are very NON-REACTIVE (Like to exist alone). • What are the Noble Gases? He, Ne, Ar, Kr, Xe, Rn

33. Lanthanides and Actinides • The lathanides are actinides are transition metals. • They are part of period 6 and 7, however they are placed below the table so that it fits on one page. • Locate the atomic numbers of the lanthanides and actinides. You will notice that they fill in the gaps in atomic numbers between Ba & Hf and Ra & Rf.

34. Transuranium Elements • These are elements listed after Uranium (92) on the periodic table. • Transuranium elements were synthesized and identified in laboratory experiments through the use of nuclear accelerators. • They are not naturally found on earth.

35. 1. METALS • Physical properties • Solids at room temperature (250C) • Luster (shininess) • Good conductors of heat and electricity • High density (Heavy for its size!) • High melting point • Ductile (thin wire) • Malleable (thin sheets)

36. 1. METALS • Chemical properties • Tend to LOSE electrons when bonding • form positive ions – ex. K+, Al3+ • Sometimes corrode (disappear slowly by chemical damage) or rust (reacts with oxygen)

37. 2. NON-METALS • Physical properties (tend to be the opposite of metals) • Mostly gases at room temperature • No luster (dull) • Non-conductors of heat and electricity • Low density • Low melting point • Brittle (breaks easily)

38. 2. NON-METALS • Chemical properties • Tend to GAIN electrons when bonding

39. 3. SEMI-METALS (Metalloids) • Tend to have both metallic and non-metallic physical and chemical properties. • For example, a semi-metal may be shiny like a metal, but cannot conduct electricity.

40. Periodic Table Websites • http://www.rsc.org/periodic-table/ • http://www.chemicalelements.com/index.html • http://www.webelements.com/pictures.html