# Using the periodic table - PowerPoint PPT Presentation

Using the periodic table

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Using the periodic table

## Using the periodic table

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##### Presentation Transcript

1. Using the periodic table chapter 4 & 11

2. Using the periodic table for electron configuration • The period relates to the energy level of electrons • Therefore H and He only have electrons in the 1st energy level • Li, Be, B, C ,N ,O ,F and Ne have electrons up to the 2nd energy level

3. You can determine the orbital by the placement For these elements the last electron is in the s orbital for these elements the last electron is in the p orbital For these elements the last electron is in the d orbital For the elements the last electron is in the f orbital

4. Determining the number of electrons in the last energy level • count the number of elements to the left edge of the “section” • For example Al • It is the first element in the 2nd row of p filling elements • The last electron for aluminum will be the first electron possible in the 2nd p

5. Continuing… • Al • The last electron will be the first possible in the 2nd p • 1 s __ • 2 s __ p __ __ __ • 3 s __ p __ __ __ d __ __ __ __ __

6. Condensed electron configuration • long electron configurations are not normally written out because it gets rather repetitive • Instead it is condensed, by starting from the previous Noble gas and adding shells to it. • For example K • [Ar]4s1 • This is the same as saying everything that is in Ar (1s22s2p63s2p6) +4s1 • Zr • [Kr]5s24d2 -> [Kr] 4d25s2

7. To Determine the Condensed electron configuration • Start at the previous noble gas (lower atomic number) • Write out every element in order of atomic number to your given • Determine which shell all elements are filling. The number of elements in that shell is your superscript number.

8. For Iron • Previous Noble Gas----Ar • Write all elements • K Ca Sc Ti V Cr Mn Fe • These fill 4 s • These fill 3 d • So it is • [Ar]3d64s2

9. Lone electron in the 5d or 6 d • Odd exception • Lanthanum’s last electron fills the 5d orbital. • Ce has its last electron fill in the 4f, and the one from 5d (La) jumps to 4f. • The next elements all fill up the 4f until Gadolinium which fills up the 5d again. • A similar “jumping” of one electron occurs with the actinide series

10. Different Periodic Tables • The electron “jumping” is why there are two forms of the periodic table in common usage. • One has lanthanum and actinium in with the d filling elements. • The other has lanthanum and actinium with the f filling elements

11. Homework • Ignore the exception for all problems • For the following elements • fill in the last shell only of the orbital diagram and do the condensed electron configuration • Ti, Cl, Sr, Sn and O