Electron Configuration 123

8/19/2019 Electron Configuration 123

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Energy Levels of Electrons

© 2014 John Wiley & Sons, Inc. All rights reserved.

Bohr’s idea of quantized energy levels does have

parallels in quantum mechanics.

For example, quantum mechanics predicts discrete,

quantized principal energy levels for electrons in

an atom.

Principal energy level (n)

provides a general idea of thedistance

of an electron from the nucleus(as n increases, so does the

distance

from the nucleus)n can !e a positive integer (",#,$,

etc.)


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%ach energy level can !e divided into su!levels.

%ach su!level corresponds to a di&erent type

of or!ital that can house electrons.

Principal quantum level n '"

ontains only one su!levelor!ital ("s or!ital)

*he or!ital is spherical in nature,

as are all s or!itals.

*he or!ital is a space +here an electronhas a

- pro!a!ility of !eing located.


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/o+ many electrons can 0t in an or!ital1

%lectron spin is represented !y arro+s ( or )

Pauli %xclusion Principle an atomic or!ital can holdt+o

electrons, +hich must have opposite spins.


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Principal quantum level n '#

ontains t+o su!levelsor!itals (#s and # p or!itals)

*he #s or!ital is spherical li2e a "s or!ital,

!ut larger and higher in energy.

*he # p su!level consists of three or!itals px

, py

and pz.

*he shape of the $ or!itals is the same3

they di&er in their orientation in space.

4 total electrons can occupy the $ p or!itals of asu!shell.

%ach p or!ital has t+o lo!es.


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Principal quantum level n '$

ontains three su!levelsor!itals ($s, $ p and $dor!itals)

*he 5 $d or!itals have unique shapes relative

to s and p or!itals.

"- total electrons can occupy the

5 d or!itals of a su!shell.


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6ith each ne+ principal quantum level,

a ne+ su!levelor!ital type is introduced.

7uantum 8evel 9ummaryPrincipal 7uantum

8evel (n)9u!levels

" 1s # 2s 2 p 2 p 2 p

$ !s ! p ! p ! p !d !d !d !d !d

: 4s 4 p 4 p 4 p 4d 4d 4d 4d 4d 4f 4f 4f 4f 4f 4f 4f




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6hat is the maximum num!er of electrons

in a :d su!level1

a. #

!. :

c. 4

d. "-

;ny d su!level has 5 total or!itals.

*+o electrons can !e housed in eachor!ital.

nergy eve s o ec rons"r#ctice



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6hat is the maximum num!er of electrons that can

occupy the n ' $ su!level1

a. <

!. #

c. "<

d. "-

*he n ' $ su!level has $ types ofor!itals

s ("), p ($), and d (5).

*+o electrons can occupy each or!ital.

( x # ' "


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/ydrogen consists of a nucleus +ith one proton

and one electron in a "s or!ital.

/o+ are electrons treated in more complicatedatoms

that contain multiple electrons1

=uidelines for 0lling electrons

;ssuming multielectron atoms have or!itals

similar to that of the hydrogen atom,

rules for 0lling electrons can !e developed.

". >nly up to t+o electrons can occupy an or!ital.#. %lectron +ill occupy lo+er energy or!itals 0rst.

>r!ital energies s ? p ? d ? f for a given n value.

$. %ach or!ital in a su!level must contain an electron!efore another electron can !e added to any of the

or!itals.

o$ c r%c %re o e rsEle$ents



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*hree +ays of depicting atomic and electronic

structure@) ;tomic 9tructure Aiagrams

Aepict !oth the nuclear and electronic structure

@@) %lectron con0guration

%ach or!ital is listed, in order of increasing energy,

+hile depicting the num!er of electrons in

each or!italsu!level.




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@@@) >r!ital Aiagram

Boxes represent or!itals and electron spinsare represented as arro+s.

$ p

*hree +ays of depicting atomic and electronicstructure




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/ydrogen

>r!ital Aiagram>r!ital Aiagram

"s1

%lectroncon0guration

"s2

%lectroncon0guration

/elium

"s2#s"

8ithium

"s "s

"s2#s#

Berylium

"s #s "s #s




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Boron

"s2#s## p"

"s #s # p

ar!on

"s

2

#s

#

# p

#

"s #s # p

ote the electrons are in di&erent or!itals per Cule$.

*he similar spin +ill !e discussed shortly.

Filling the p su!shell




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Filling the p su!shell

>xygen

"s2#s## p:

itrogen

"s2#s## p$

"s #s # p

ote the electrons are in di&erent or!itals per Cule$.

*+o electrons must !e paired in one p or!ital.

"s #s # p




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Filling the p

su!shell

eon

"s2#s## p4

"s #s # p

Fluorine

"s2#s## p5

"s #s # p

;ll electrons are paired in the p shell.




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Beyond e 9odium

"s2#s## p4$s"

"s #s # p $s

Begin 0lling the $n shell.



o$ c r%c %re o e rs


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Dalence %lectrons

electrons located in the highest energy(outermost) or!itals of an atom.

Dalence electrons participate in !onding to form

molecular compounds (see hapter "").

*he column num!er (";E;) in the periodic ta!legives the valence electrons of an element.

>xygen

%lectron con0guration

"s2#s## p:

>utermost valence electrons are in the n '#su!shell3

oxygen has 4 total valence electrons.

%xample




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/o+ many valence electrons does phosphoruscontain1

a. 5

!. <

c. "5

d. "<

P is in =roup 5;.@t +ill contain 5 valence electrons.

%lectron on0guration

"s##s## p4$s#$ p$

Dalence electrons

Electronic (on)g%r#tion "r#ctice



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6hich element could have the follo+ing

electron con0guration1

"s

#

#s

#

# p

4

$s

#

$ p

4

a. l

!. a

c. ;r

d. 9

*he element contains "< electrons.

@t must also contain "< protons.

;tomic num!er "< ' argon.


Electronic (on)g%r#tion "r#ctice


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/o+ does the electronic structure of atoms relateto their

positioning on the periodic ta!le1

>rigins of the Periodic *a!le

Gendeleev and Geyer proposed organizing elements

!ased on increasing atomic masses.*heir ideas formed the origins of the modern

periodic ta!le.

Electron Str%ct%res #nd the"eriodic *#+le



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ele$ents ith si$il#r-ro-erties.

columns (groupsfamilies)

ro+s(periods)

incre#sing

/#to$icn%$+er

*he odern "eriodic *#+le



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Period num!er corresponds to the highest

principal quantum num!er n of the elements.

=roup num!ering !y num!ers "H"< or

+ith num!ersletters (i.e., ;).

; groups are the representative elements.

B groups are the transition elements.




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a. /alogens

!. o!le gases

c. ;l2ali metals

d. ;l2aline earth metals

Gagnesium is a mem!er of +hat group ofelements1

"eriodic *#+le "r#ctice



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=roup ommonalities ;ll elements in a group

have similar valence electron con0gurations.*his often leads to similar reactivity

of elements in a group.

Because electron con0gurations of larger elements

arevery long, a shorthand notation is used that

highlights valence electrons.a IeJ$s"

*his indicates the electron con0guration of sodiumis that for e +ith an additional $s" electron.

*he shorthand electron con0guration al+ays usesthe

previous no!le gas core +ith the valence electrons

for the element of interest.

%xample




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@nitially, one may expect to 0ll $d electrons!efore :s electrons.

/o+ever, !ased on reactivity of the elements K anda,

they resem!le metals +ith valence electrons in sor!itals.K I;rJ:s"

a I;rJ:s#

%lements #"E$- are transition elements +hereelectrons no+ 0ll in the $d su!shell.

>nce the $d su!shell is 0lled, the : p shell !egins to

0ll.

%xample

Electron illing



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9u!level Filling Aiagram


Electron illing


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a. K

!. P

c. Fluorine

d. a

*he electron con0guration I;rJ :s" is theground state electron con0guration of

*he element contains " valenceelectron

in the fourth period (due to n ' :).

Electron illing "r#ctice



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*he electron con0guration IeJ $s#$ p", is theground state electron con0guration of

a. a!. ;l

c. ;r

d. 9

*he element contains $ valenceelectrons

in the third period (due to n ' $).


Electron illing "r#ctice


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=roups of elements sho+ similar chemical

properties!ecause of similarities in their valence electrons.

=roup num!er equals the total num!er of

outermost valence electrons.

%xample =roup H contains the

ns#

np5

valence con0guration

(he$ic#l "eriodicity



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8ist the $ !asic characteristics of electromagneticradiation

"-." %lectromagnetic Cadiation

%xplain the relationship !et+een the line spectrum

and the quantized energy levels of an electron in anatom.

"-.# *he Bohr ;tom

Aescri!e the principal energy levels,

su!levels and or!itals of an atom.

"-.$ %nergy 8evels of %lectrons

Le#rning 6+7ectives


i +7 i


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Lse the guidelines to +rite electron con0gurations.

"-.: ;tomic 9tructure of the First "< %lements

Aescri!e ho+ the electron con0gurations of the

atomsrelate to their position on the periodic ta!le and

+rite electron con0gurations for elements !ased

on their position on the periodic ta!le.

"-.5 %lectron 9tructures and the Periodic *a!le

Le#rning 6+7ectives

Electron Configuration 123

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