seoul national univ. chemistry for biology students 2015 ch.1 pptx

7/24/2019 Seoul National Univ. Chemistry for Biology students 2015 ch.1 pptx

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- Chemical Principles (Sixth Edition), Peter Atkins, Loretta Jones and Leroy Laverman-

W ! "reeman-#$%#

Week % & #' Chapter % - Atoms' he *ant*m World

Week +' Chapter # - Chemical onds

Week ' Chapter + - .olec*lar Shape and Str*ct*re

Week /' Chapter - he Properties o0 1ases

Week 2' Chapter / - Li3*ids and Solids

Week 4' .idterm Exam

Week 5' Chapter 4 - hermodynamics' he "irst La6Week 7' Chapters 4 & 5 - hermodynamics' he "irst La6 & hermodynamics' he Second and

hird La6s

Week %$' Chapters 5 & 7 - hermodynamics' he Second and hird La6s & Physical E3*ili8ria

Week %%' Chapters 7 & %$ - Physical E3*ili8ria and Chemical E3*ili8ria

Week %#' Chapters %$ & %% - Chemical E3*ili8ria & Acids and ases

Week %+' Chapters %% & %# - Acids and ases & A3*eo*s E3*ili8ria

Week %' Chapter %# - A3*eo*s E3*ili8ria & C*rrent opics (90 ime Permits)Week %/' "inal Exam

- ' #$:, ' %$:, ' +$:, ' $:

/$+ #7 (555-25%4); (cys$2%


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Chapter 1.

Atoms: The Quantum World


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Key Ideas Atomic Structure in terms of Quantum Mechanics

Goal Periodic variation of atomic properties

(periodic table)

Quantum mechanics Atomic structure

Atomic properties Chemistry


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Chemical insight

Failure of classical mechanics on electrons

Quantum mechanics in the early 2th century

!"#$S%!&A%!"& A%'MS!"#$S%!&A%!"& A%'MS

%hree maor subatomic particles electrons* protons* neutrons


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Components of the Atom

> Atomic theory raised more questions than it answered

? Could atoms be broken down into smaller particles

? 100 years after atomic theory was proposed, the answers were provided by experi

ment


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Fundamental Experiments

> !! "homson, Cavendish #aboratories, Camb

rid$e, En$land> Ernest %utherford

? &c'ill (niversity, Canada

? &anchester and Cambrid$e (niversities, En$land


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1.1. The Nuclear Model of the Atom

Investigating Atoms


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Electrons> First evidence for subatomic particles came from thestudy of the conduction of electricity by $ases at lowpressures

? !! "homson, 1)*+? %ays emitted were called cathode rays

? %ays are composed of ne$atively char$ed particlescalled electrons

? Electrons carry unit ne$ative char$e -1. and havea very small mass 1/000 the li$htest atomic mass.


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Cathode %ay Apparatus


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The Electron and the Atom> Every atom has at least one electron

> Atoms are known that have one hund

red or more electrons> "here is one electron for each positive

char$e in an atom

> Electrical neutrality is maintained


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Protons and Neutrons The Nucleus

> Ernest %utherford, 1*11

> ombardment of $old foil with 2 particles helium atoms without electrons.

? Expected to see the particles pass throu$h the foil

? Found that some of the alpha particles were deflected by the foil

? #ed to the discovery of a re$ion of heavy mass at the center of the atom

Alpha particles (named after and denoted by the first letter inthe Greek alphabet, ) consist of two protons and two neutronsbound together into a particle identical to a helium nucleus,which is generally produced in the process of alpha decay, butmay be produced also in other ways and given the same name.

From wikipedia.org


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%utherford ackscatterin$


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"he 3lum-3uddin$ &odel> !! "homson proposed the atom

as a positively char$ed sphere

? 4ithin the sphere are electrons

? 3lum-puddin$ or raisin-breadmodel


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Rutherfords Model

> %utherford5s experiment revealed a small, dense core with positive char$e

? Electrons are outside this core? &ost of the atom is empty space


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Nuclear Particles

1! 3rotons? &ass nearly equal to the 6 atom

? 3ositive char$e

! 7eutrons? &ass sli$htly $reater than that of the proto

n

? 7o char$e


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Mass and the Atom

> &ore than **!*8 of the atomic massis concentrated in the nucleus

> "he volume of the nucleus is much smaller than the volume of the atom


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9ubatomic 3articles


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1.3. Atomic Spectra


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+almer series (,--.)

(/ohann +almer* ,-2.0,-1-* Siss mathematics schoolteacher)

3ydberg formula (/ohannes 3ydberg* ,---)


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Absorption spectrum of 4

Absorption lines have the same wavelengths as the emission lines!

Absorption spectra to identify elements in the outer layers of stars

Fig ,5,, Sun4o to e6plain the e6perimental observations7

,5 An electron in an atom can have only certain energies5

25 A spectral line arises from a transitionbeteen to ofthe alloed energies5


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1.4. Radiation, uanta, and !hotons

"lac#$od% Radiation &

'

uanti(ation of )lectromagnetic *ave

h = 6.626 10-34Js !lan" #onstant$

uantum Theor%


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8ltraviolet catastrophe9Any hot body should emit intense short:avelength radiations

according to a prediction of classical physics* contrary to the

Stefan:+olt;mann la and =s hypothesis9 Quantumof radiation energy* Ma6 Planc>

(,1* ,1,-)

Planc>=s constant


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Planc>=s hypothesis e6plains the S:+ la and


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!hotoelectric effect

%&per'mental results

1. (o ele#tron 's e)e#ted *hen +.

2. %le#trons are 'mmed'atel, e)e#ted

een ' +

3. The "'net'# ener/, o e- l'nearl,

'n#reases *'th +


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%he +ohr fre@uency condition e6plains the spectrum of 45


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1.+. The *ave!article -ualit%

'ra#t'on and 'ntereren#e *ae

!hotoele#t'# ee#t part'#le

de "roglies material /ave

1.0. The ncertaint% !rinciple2eisen$erg uncertaint% principle


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,5E %he 8ncertainty Principle

Classical mechanics definite traectory* both the location and

momentum specified precisely

Quantum mechanics ave:li>e traectory

4eisenberg uncertainty principle (,12)complementarity of location and momentum

The location and momentum of a particle are complementary;

ie both the location and the momentum cannot be "nown

simultaneously with arbitrary precision


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$6 ,5a of a marble of ,5 g ith a speed >non to

ithin mms7

$6 ,5b of an electron confined to ithin the diameterof a typical atom (25 pm)7

For macroscopic obects* the uncertainty principle can be neglected5

For subatomic particles* it is of profound importance5


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1.. *ave functions and )nerg% evels

Wae un#t'on $

!roa'l't, dens't, 2$

Schr5dinger e6uation

2 = %


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,5


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For a one:dimensional system in apotential energy #($)


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%herefore* J($) satisfies the SchrHdinger e@uation*


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Fig ,52.


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%4$ 4K?3'&$" A%'M%4$ 4K?3'&$" A%'M

,) An electron is described by a avefunction governed

by the SchrHdinger e@uation5

2) %he nuclear model for an atom

%o e6plain the ladder of energy levels suggested by

spectroscopy


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,5- %he Principal Quantum "umber

Constraints (boundary conditions) in solving

the SchrHdinger e@uation

Quanti;ation of energies* discrete energy levels corresponding

to a set of @uantum numbers

%o solve the SchrHdinger e@uation for y and energy levels of

an electron in a hydrogen atom* the potential energy term #

in the hamiltonian%is needed5


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%he solution by SchrHdinger (,12)

$nergy levels of a hydrogen atom Fig ,52-

For other one:electron atoms such as 4eL* * C.Lith atomic number&*

&2dependence

,) nucleus of charge&e 2)&times closer distance to the nucleus

-egenerac%- d'erent uantum states ha'n/ the same ener/,


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,51 Atomic 'rbitals

Atomic orbitals avefunctions of electrons in atoms

(orbital ave:li>e orbit)


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?etailed solutions of the SchrHdinger

e@uation for a hydrogen atom re@uire three

@uantum numbers5

%hree dimensional boundary

conditions

Principal @uantum number (n)energy N si;e

Fig ,5IE


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Shell atomic orbitals of the same principal

@uantum number n

As nincreases* the energy (0,n2) and the nucleus:electron

distance (n2) increase5

All the orbitals of a given shell of hydrogen:li>e atoms have

the same energy degenerate

'rbital angular momentum @uantum

number (l) shapeAngular momentum


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lB * ,* 2* * n0 , ndifferent values of l nsubshells

Subshell group of orbitals ith the same value of l

'rbital angular momentum of an electron in a subshell

B measure of the rate at hich the electron

circulates around the nucleus

s(sharp) lB *p(principal) lB ,* d(diffuse)lB 2*f(fundamental) lB I*g* h*


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Shape of or$itals


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Boundary surfacea smooth surface that encloses most (typically 1O) of the

electron cloud

Alls:orbitals have spherical boundary surfaces

(ith internal structures such as nodes)5


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p:'rbitals

%he +oundary surface of

each p orbital hasto lobes

andone nodal plane5

I orbitals in each subshell

Ap:electron ill never be

found at the nodal plane nor

at the nucleus5


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d:'rbitals

. orbitals in each subshell


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f:'rbitals Figs ,5I-

%otal number of orbitals in a shell B n2


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n: pr'n#'pal uantum numer

related to the s'5e and ener/, o the

or'tal

l: or'tal an/ular momentum uantum

numer l = 0 1 2 ... n-1$

related to the or'tal an/ular

momentum o the ele#tron

ml: ma/net'# uantum numer ml= l l-

1 l-2 + -l$

7 related to the or'entat'on o the

or'tal mot'on o the ele#tron


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1.17. )lectron Spinms: sp'n ma/net'# uantum numer ms= 81926 -192$

7 related to the sp'n o ele#tron


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1.11. The )lectronic Structure of 2%drogen Atom

In the ground state

7 n = 1 l = 0 ml= 0 ms= 8192 or -192

In the e8cited state

7 n = 2 our or'tals$

n = 3 n'ne or'tals$

n = " "2or'tals$

n = 'n'n'te 'on'5at'on$

e/enera#,: same ener/, or all or'tals 'n the same n


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MA"K:$G$C%3'" A%'MSMA"K:$G$C%3'" A%'MS

,5,2 'rbital $nergies

&reater attractionsbeteen electrons and the nucleus

4igher charge of the nucleus

3epulsionsbeteen electrons

4eatom ith 2 electrons

Analytical solution impossible!'umerical solution!


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4ydrogen:li>e atoms

one electron* no electron:electron repulsion

All orbitals of a given shell are degenerate

(of the same energy)5

Many:electron atoms

electron:electron repulsion

'rbitals of a given shell are

nondegenerate(of different energies)5

Fig ,5,


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1.19. :r$ital )nergiesCoulom potent'al or man,-ele#tron atoms

r1: e1nu#leus

r2: e2nu#leus

r12: e1e2

;or e8ample, in a helium atom,

Shielding and !enetration effect

- %a#h ele#tron 's sh'elded , the other e-$s.

;e

: ee#t'e nu#lear #har/e

- e-$s 'n p or'tal penetrate less than e-$s 'n s

or'tal 7 %s< %p

energ% split


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Shieldingdue to the electron:electron repulsions

'ther electrons do not bloc>the influence of the nucleus they

simply provide additional repulsive coulombic interactions

thatpartly counteract the pull of the nucleus5

$ffective nuclear charge&eff&


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Penetration ans:electron can be found very

close to the nucleus hile ap:electronapproaches the nucleus less closely due to its

orbital angular momentum (JlB,() B )5


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Ans:electronpenetrates morethan ap:electron through

the inner shells of the atom5 Ans:electron is shielded lessthan ap:electron (ans:

electron feels a higher nuclear charge)5

Ans:electron isbound more tightlythan ap:electron5

Ans:electron has a loer (more negative) energythan ap:

electron5

%he order of energies of orbitals in a given shell due to effects

of penetration and shielding9

sp df

A s:electron may even have a loer energy than that of a Id:

electron of the same atom5


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1.13. The "uildingp !rinciples

!auli e8clusion principle

no more than 2 e-$s 'n an,

/'en or'tal

#losed shell

#ore ele#tron

alen#e ele#tron

2unds Rule

7 parallel sp'n rather than pa'red

alen#e shell


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Pauli exclusion principle (Wolfgang Pauli, 1925)

"o more than to electrons may occupy any given orbital5


62/90

Period , nB ,

Closed shell fullyoccupied shell

Period 2 nB 2

#alence shellpartiallyoccupied shell ith the largest n


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+uilding:up principle(Aufbau principle)

1 Pauli exclusion principle! "axi#u# of 2 $%elec&rons per ori&al (fer#ions)

2 Hund's rule! $$ spins &o differen& ori&als, if aailale


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Period I nB I

Period nB * first long (, IdL 2 sL E pB ,-) period

of the periodic table

,5 %he sorbitalhas a slightly loer energy than those of

Idorbitals5


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25 'nce they contain electrons* the Idorbitals lie loer in

energy than the sorbital5%ransition metals &roup I (Sc) to &roup ,, (Cu)

Properties of the d:bloc> metals are transitionalbeteen the

s: and thep:bloc> elements5

I5 %he half:full Id.and the full Id,have a loer energy5


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Period . nB .* long (, dL 2 .sL E .pB ,-) period

1 he 5sori&alhas a sligh&ly lo*er energy &han &he

+dori&als

2 nce &hey con&ain elec&rons, &he +dori&als lie lo*er inenergy &han &he 5sori&al

- .isrup&ions due &o ery close energies of +dand 5s

ori&als


67/90

Period E nB E* f:orbitals (Es f .d Ep)

Ganthanoids(lanthanides) Ga (&B .) to Gu (&B ,)

cf5 3are earth elements ,. lanthanoids L Sc L K

1 +f/ori&als

(disrup&ionsdue &o ery close energies of +fand 5dori&als)

2 5d/ori&als

- 0p/ori&als


68/90

,5 Add electrons in the order shon in Figs5 ,5, and ,5

observing the Pauli e6clusion principle5

n u##ary,

25 4und=s rule hen more than one orbital in a subshell are

available5

I5 Parallel spins for electrons in different orbitals paired

spins for electrons sharing an orbital5

5 &roup number B number of valence electrons* Period

number B n

1 14 )l t i St t d th ! i di T $l


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1.14. )lectronic Structure and the !eriodic Ta$le


70/90

4e belongs to &roup ,-#!!! due to the filled shell5

4* one electron short of a noble gas configuration* can act li>e amember of &roup ,#!!!5

Main groupss: andp:bloc>s

3oman numerals (!:#!!!) ith or ithout TAT

%he number of valence electrons is e@ual to the 3oman

numerals5

For ,:,- group labels* the number of valence electrons is

e@ual to (&roup number 0 ,)5


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%4$ P$3!'?!C!%K 'F A%'M!C P3'P$3%!$S%4$ P$3!'?!C!%K 'F A%'M!C P3'P$3%!$S

&effvs5& effective nuclear charge for the outmost valence electron

&effB&0 (

( average number of electrons inner to the electron in @uestion


72/90

Across the periodic table (left to right)*&effincreases (generally)5

'versimplified9 !f the Isvalence electron ere completely outsidethe ten core electrons (perfect shielding)*

&eff("a) &eff(Mg)5

3ess si#plified! 1) 4alence elec&rons can also pene&ra&einner shells depending on &he lalues

2) ore elec&rons are no& all e6ually

effec&ie in shielding alence elec&rons

-) 4alence elec&rons shield one ano&her for &he

nucleus charge a li&&le i&


73/90

?on the periodic table (top to bottom)*

&effincreases (slightly)5

'versimplified9&eff(Gi) B&eff("a)

Gess simplified9 %he 2s: and 2p:electrons have loer

shielding capabilities than the ,s:electrons5

1 1+ At i R di


74/90

1.1+. Atomic Radius

related to


75/90

Periodic variation in the atomic radii of the elements

?on a group* nincreases5

Garger shell Garger radiusAcross a period*&eff increases5

Stronger attraction Smaller radius


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,5,E !onic 3adius

!onic radius share of the distancebeteen neighboring ions in an ionic solid


77/90

isoelectric ions


78/90

All cationsare smallerthan their parent atoms

attraction beteen e6cess protonsand (loer n) electrons

All anionsare largerthan their parent atoms repulsion

beteen e6cess electrons

!soelectronic same electron

configuration F0* "e* "aL* Mg2L


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1 1 Ioni(ation )nerg%


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1.1. Ioni(ation )nerg%

Ta$le= the 1st

I > mol1

'

The m'n'mum % need to remoe an ele#tron rom an atom 'n the /as phase.

? &g' @ ?&g' e&g'I B )&?' C )&?'

T,p'#all,

1de#reases do*n a /roup

T,p'#all, 1'n#reases a#ross a per'od


81/90

Periodic property

Small but regular departures from the general trend due to the

e6tra stabilityof a closeds2subshell and a half:filledpIsubshell

Fig ,5.,


82/90

S% ,5,A

2nd ioni;ation energy


83/90

$vidence of a shell structure Fig ,5.2

Ta$le= the 1stand 9ndI > mol1'


84/90

1 1D )lectron Affinit%


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electron affinit% > mol1'

1.1D. )lectron Affinit%The % released *hen an ele#tron 's added to an atom 'n the /as phase.

? &g' e&g' @ ?&g' )ea&?' B )&?' C )&?'

T,p'#all, %ea'n#reases a#ross a per'od

T,p'#all,

%eade#reases do*n a /roup


86/90

Periodic property

much less periodic than the variations in radius andioni;ation energy

4ighest toard the (upper) right sideof the periodic table e6cept

for noble gases


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"oble gases have negativeEeadue to their stable closed shell5

&roup ,#!!positive firstEeaand very negative secondEea5


88/90

&roup ,E#!

positive firstEea

and negative secondEea

5

"o gaseous atom ith a positive electron affinity for a second

electron e:e repulsion

?oubly charged anions are stable only hen surrounded

by cations or solvent molecules5


89/90

,52 ?iagonal 3elationship

?iagonal relationship similarity beteen

diagonal neighbors in the main groups

,) Atomic radius increases don a

group and decreases across a

period5

2) !oni;ation energy decreases don a

group and increases across a period5

Fig ,5.-

?iagonal neighbors have similar

randI,5

Similar chemicalproperties

1.91. The Eeneral !roperties of the )lements


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seoul national univ. chemistry for biology students 2015 ch.1 pptx

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