Special topics for sol 2 3 rd power point
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Special Topics for SOL 2 3 rd Power Point. Periodic Trends (Chap 14). Shorthand Electron Configurations. Shorthand configurations are a useful tool. Let’s look at an example for Y, Z=39 The electron configuration for yttrium is 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 1

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Special Topics for SOL 2 3 rd Power Point

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Special topics for sol 2 3 rd power point

Special Topics for SOL 23rd Power Point

Periodic Trends (Chap 14)


Shorthand electron configurations

Shorthand Electron Configurations

  • Shorthand configurations are a useful tool.

  • Let’s look at an example for Y, Z=39

  • The electron configuration for yttrium is 1s22s22p63s23p64s23d104p65s24d1

  • To do a shorthand configuration, we use the noble gas preceding the element and we put that in brackets(the bold and italics part)

  • That’s Kr and then we also just write whatever is left over.

  • [Kr] 5s24d1


You try

You Try…

  • Do a shorthand configuration for

  • Fe

  • Br

  • Rb


The answers

The Answers…

  • Do a shorthand configuration for

  • Fe = [Ar]4s23d6

  • Br = [Ar]4s23d104p5

  • Rb = [Kr]6s1


Objective b http www rsc org chemsoc visualelements pages data intro groupvii data html

Objective Bhttp://www.rsc.org/chemsoc/visualelements/PAGES/data/intro_groupvii_data.html

  • Notice that the halogens all have an ending configuration of ns2np5. That means they have 7 valence electrons.

  • Similarly, alkali metal have 1 valence electron. Noble gases have 8, etc. All transition metals have 2.

F[He]2s22p5Cl[Ne]3s23p5

Br[Ar]3d104s2 4p5I[Kr]4d105s2 5p5

At[Xe]4f14 5d106s2 6p5


Objective b

Objective B

  • All of the transition metals have 2 valence electrons, with 2 exceptions. “d” electrons are not valence electrons. Why not?

  • Transition metals are where the d orbitals are being filled up. Here are the electron configurations for all of them.

Sc[Ar]3d14s2Ti[Ar]3d24s2

V[Ar]3d34s2Cr[Ar]3d54s1

Mn[Ar]3d54s2Fe[Ar]3d64s2

Co[Ar]3d74s2Ni[Ar]3d84s2

Cu[Ar]3d104s1Zn[Ar]3d104s2


Objective b1

Objective B

  • Notice that Cr and Cu are “exceptions.”

  • They both have 1 valence electron. They do this because in the case of Cr, moving an electron from the 4s level to the 3d level gives us a half full set of d orbitals.

  • That’s more stable than if Cr would have followed the pattern, and ended with “4s23d4”

Cr[Ar]3d54s1


Objective b2

Objective B

  • Similarly, Cu has 1 electron in the 4s energy level and 10 in the 3d level, because having a full set of d electrons is also more stable.

Cu[Ar]3d104s1


Objective b3

Objective B

  • The “inner transition metals” are the lanthanide and actinide series.

  • That’s where the f electrons are filled up.

  • That’s about all I’m going to say about that.


Objective c

Objective C

  • The periodic table allows you to predict trends in certain properties.

  • Get out a periodic table and put these trends as notes on your periodic table.

  • The first trend is Atomic radius.

  • Atomic radius is the size of the atom. It’s defined as ½ the distance between two nuclei which are bonded together.


Objective c1

Objective C

  • Ionic radius is another property

  • It is the size of an ion. Ionic radius is fairly similar to atomic radius.

  • A positive ion is also called a CATION.

  • A negative ion is also called an ANION.

  • A cation is always smaller than the atom it is formed from.

  • An anion is always larger than the atom it is formed from.


Objective c http www chem1 com acad webtext atoms atpt images ionic radii jpg

Objective Chttp://www.chem1.com/acad/webtext/atoms/atpt-images/ionic_radii.jpg

  • Since cations lose electrons to form positive ions and anions gain electrons to form negative ions, it should make sense that they are SMALLER than the atom.


Objective c2

Objective C

  • Ionization energy is the amount of energy required to remove an electron from a gaseous atom.

  • The energy required to remove the first electron is called the FIRST IONIZATION ENERGY.

  • The energy required to remove the second electron is the second ionization energy. And so on…

  • Metals always have LOWER ionization energies than nonmetals.

  • That is because metals tend to lose electrons and nonmetals tend to gain them.


Objective c3

Objective C

  • It is VERY MUCH easier to remove a valence electron (an electron in the highest energy level) than an “inner core” electron.

  • The inner core electrons are ANY electrons which are not VALENCE electrons.

Na = 1s22s22p63s1

White = inner core electrons and Blue = Valence electrons


Objective c http www knowledgerush com wiki image 8 87 linuspauling jpeg

Objective Chttp://www.knowledgerush.com/wiki_image/8/87/LinusPauling.jpeg

  • Electronegativity is measured on a scale from 0.0 to 4.0.

  • By definition, F is the most electronegative element at 4.0.

  • Nonmetals have a high electronegativity.

  • Metals have a low electronegativity.


Electronegativity

Electronegativity

  • Think of this as the “greediness” of an atom not only holding on to it’s own electrons, but ALSO wanting to “steal” electrons from other atoms.


The trends

The Trends

  • Atomic Radius AND Ionic Radius increase as you go down a group.

  • Atomic Radius AND Ionic Radius decrease as you go from left to right across a period.

  • Electronegativity AND Ionization Energy decrease as you go down a group.

  • Electronegativity AND Ionization Energy increase as you go from left to right across a period.

Note the trends are opposites. Draw some arrows on your periodic table to help you remember the trends.


The end

The End


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