Trends Review, History of the Periodic Table, Oxidation Numbers

• Objective– Today I will be able to:

• Apply the trends of ionization energy, electronegativity and atomic radius to problem solving.

• Explain the history of the periodic table.• Identify the oxidation numbers for the families of elements on the

periodic table.• Evaluation/ Assessment

– Informal assessment – Listening to group interactions and discussions as they complete the analyzing the periodic trends graphing activity

– Formal Assessment – Analyzing student responses to the exit ticket, graphs and periodicity practice

• Common Core Connection– Build Strong Content Knowledge– Value Evidence– Reason abstractly and quantitatively – Look for and make use of structure

Lesson Sequence

• Warm – Up• Evaluate: Review

Chapter 5 worksheet• Informal assessment

• Elaborate: Periodicity Practice– Formal assessment

• Explain: history of the periodic table and oxidation numbers

• Elaborate: Practice and Exam Review– Informal Assessment

• Evaluate: Exit ticket• Formal assessment

Warm - Up

• What is ionization energy?– How does it change down a family?• Why does this trend occur?

– How does atomic radius change across a period?• Why does this trend occur?

• How does an atomic radius compare to an ionic radius?

Objective

• Today I will be able to:• Apply the trends of ionization energy,

electronegativity and atomic radius to problem solving.

• Explain the history of the periodic table.• Identify the oxidation numbers for the families of

elements on the periodic table.

Homework

• Periodic Table (mini-exam) on Thursday and Friday next week

• STEM Fair– Final Research Paper due Monday December 17– In Class Presentations Wednesday January 23

Agenda

• Warm – Up• Study guide• Review Homework• Periodicity Practice Worksheet• History of the Periodic Table Notes• Oxidation Number Notes • Exam Review• Exit ticket

Review HW – Chapter 5 Worksheet

Discuss answers to selected problems and then turn in

Periodicity Practice

Complete Worksheet and Review as a class

History of the Periodic Table and Oxidation Number Notes

Johann Dobereiner (1829)

• Law of Triads - in triads of elements the middle element has properties that are an average of the other two members when ordered by the atomic weight

• Example - halogen triad composed of chlorine, bromine, and iodine

John Newlands (1864)

• Law of Octaves - states that any given element will exhibit analogous behavior to the eighth element following it in the periodic table

Dmitri Mendeleev (1871)

• Developed the first Periodic Table• He arranged his table so that elements

in the same column (groups) have similar properties; increasing atomic mass

Dmitri Mendeleev (1871)

• Broke the trend of arranging elements solely by their atomic mass

• Wanted to keep elements with similar properties in the same columns

• Left gaps in his early tables; predicted elements that had not been discovered would fill in those gaps- Ekasilicon Germanium - Germanium was discovered in 1886

Dmitri Mendeleev (1871)

Henry Moseley (1913)

• Found a relationship between an element’s X-ray wavelength and it’s atomic number (number of protons)

• Periodic Law - when elements are arranged in order of increasing atomic number, their physical and chemical properties show a periodic (repeating) pattern

• The periodic law is the basis for arranging elements in the periodic table

Glenn Seaborg

• He reconfigured the periodic table by placing the actinide series below the lanthanide series

• Awarded a Nobel Prize in 1951• Element 106, Seaborgium (Sg), is named in his

honor

Oxidation Numbers

Oxidation Numbers

• Remember, most atoms strive to have eight valence electrons (some are satisfied with only two)

• Atoms will form various bonds by gaining, losing, or sharing electrons, in order to satisfy the Octet Rule

Oxidation Numbers

• An atom’s electron configuration is used to determine how many electrons need to be gained, lost, or shared

• Example – Na (11 electrons)• 1s2 2s2 2p6 3s1 – 1 valence electron• In order for Na to have eight valence

electrons, would it be easier for it to gain 7 electrons, or lose 1?

• Losing 1 is easier

Oxidation Numbers

• When Na loses an electron it becomes an Na+1 ion

• 1s2 2s2 2p6 3s1 becomes…• 1s2 2s2 2p6 – 8 valence electrons• Na carries a +1 charge because it has lost an

electron, and it now has more positively charged protons than negatively charged electrons

Oxidation Numbers

• Another Example – Fluorine (9 electrons)• 1s2 2s2 2p5 – 7 valence electrons• In order for F to have eight valence electrons,

would it be easier for it to gain 1 electron, or lose 7?

• Gaining 1 is easier

Oxidation Numbers

• When F gains an electron it becomes an F-1 ion• 1s2 2s2 2p5 becomes…• 1s2 2s2 2p6 – 8 valence electrons• F carries a -1 charge because it has gained an

electron, and it now has more negatively charged electrons than positively charged protons

Oxidation Numbers

• There is a fairly consistent pattern to oxidation numbers with families

• Transition Metals and Inner Transition Metals usually have a varying number of valence electrons

• Some don’t – Zn+2, Cd+2, Sc+2, Ag+1

Exam Review

Complete with the people in your row. If you have questions please ask

Ms. Ose

Exit Ticket

• Which element is more likely to have a higher (more negative) electron affinity, Aluminum or Sulfur?

• List the oxidation number for the following families– Alkali metals– Alkaline earth metals– Halogens– Noble Gases