KEYNOTE SPEAKER 2 - JURUSAN KIMIA FMIPA...

KEYNOTE SPEAKER 2

Misconception in Chemistry Textbooks and Teachers as Users: Case Study on the Concepts of Quantum Numbers and Electronic Configurations for

Senior High School Level in Yogyakarta, Indonesia

Professor Dr. Kristian H. Sugiyarto

Department of Chemistry Education, Faculty of Mathematics and Science

Yogyakarta State University, INDONESIA

MISCONCEPTION IN CHEMISTRY TEXTBOOKS AND TEACHERS AS USERS;

CASE STUDY ON THE CONCEPTS OF QUANTUM NUMBERS AND ELECTRONIC CONFIGURATIONS FOR SENIOR HIGH SCHOOL LEVEL

IN YOGYAKARTAby:

Kristian H. Sugiyarto

PoPulation :

1.Textbooks of chemistry for High-School circulating in Yogyakarta (~ 10 textbooks)

SamPlE : 6 textbooks

2. Chemistry Teachers as Users

SamPlE: 33 teachers from 10 Public- and 5 Private- High Schools in Yogyakarta

Method:

• Procedure :1. The content of the corresponding concepts in the

textbooks were reviewed according to scientific correctness

2. - The teachers were gathered in a class-room to respond the questioning test

- They were asked to bring their own textbook(s) and to discuss one to another, but the answers should be on his/her own individual decision

- Therefore, his/her answers should be merely based on her/his own understanding about the concepts, and no forgetful factor was considered

- The results were collected and then discussed to show the misconception

Duck !

Grand mum!

Beautiful Lady!

Misconception!

Who is him-her?What is this?

Rabbit!

MANExtreme particle?

(2) (3) (4)

(5) (6) (7) WOMENExtreme wave??Can you recognise, who he/she is ?

Concept(Original)

“Concept”(Product)t r a n s f e r

discrepancy ?"preconception, misconception, alternative framework,

students’ knowledge, explanatory system ….."

"misconception is the term commonly used to describe an unaccepted (and not necessarily wrong) interpretation of a concept illustrated in the statement in which the concept is embedded. However, van den Berg (1991) declares that in

science, "misconseption" is identical to ”wrong"

quantum numBERS

n : 1, 2, 3, 4, 5, ……., ∞

ℓ : 0, 1, 2, 3, 4, …….

mℓ : 0, ±1, ±2, ±3, ..…..

s : ½

ms :±½

What for are they?

For designating the electrons in an atom/ion/molecule, and thus

electronic configuration

How are they generated ?

????? ???

Misconception?

Only true for the first twenty element!!!

Misconception?

1s

2s

4s3p

3s2p

6s5p4d

7s6p5d4f

5s4p3d

8s7p6d5f

(c)

2s

7s

6s

5s

4s

3s

1s

6p

5p

4p

3p

2p

6d

5d

4d

3d

4f

(1)

(2)

(3)

(4)

(5)

(6)

(7)

(8)

(9)

(10)

(11)

(12)

(13)

(14)

(15)

(16)

(17)

(a)

5f

Diagram mnemonic urutan pengisian elektron pada orbital atas dasar aufbau menurut:

(a) (a) Pao-Fang Yi (J. Chem. Ed. 1947, Vol. 24, 567)(b) Uncle Wiggly (J. Chem. Ed. 1983, Vol. 60, 562)

(c) Darsey sebagai “pohon natal Pascal”( (J. Chem. Ed. 1988, Vol. 65, 1036)

(b)

1s

2s

3s

4s

5s

6s

7s

2p

3p

4p

5p

6p

7p

3d

4d

5d

6d

4f

5f

Diagram aufabu hanya benar-eksak hingga nomor atom 20

WHY?

Simplification of the complex!

Misconception?

J. Chem.Ed. Vol.55, Number 1, January, 1978, 2-6

Misconception?

J. Chem.Ed. Vol.55, Number 1, January, 1978, 2-6

Misconception?

Misconception?

3d

4s

J. Chem.Ed. Vol.55, Number 1, January, 1978, 2-6

J. Chem.Ed. Vol. 66, Number 6, June, 1989, 481-483

?

? ?

Alfabetik -numeric ?

Misconception?

Polar and Cartesian Coordinates for One Electron Model

r = 0 - , q = 0 - p , f = 0- 2 p

Important equations:z = r cos qx = r sin q cos fy = r sin q sin f, and

r2 = x2 + y2 + z2

Eq (1)SOLUTION

=

immn

anZr e CosPan

rZL

an

rZe

anmn

Znm.. )(

22

])![()!(

)!1()!)(12(

0

12

0

/3

034

30

oRBital !

• Pictures of the wavefungtion, Y or Y2 (the probability

in finding electrons):

1) Yn,ℓ,m (r,q,f)

2) Yn,ℓ, = Rn,ℓ (r )

3) Yℓ,m = Qℓ,m (q) . Fm (f)

4) Yℓ,m2 = [Qℓ,m (q) . Fm (f)]2

For “chemical practice”

3 & 4

Bentuk orbital polar: (a) fungsi cos q dan (b) fungsi cos2 qatau orbital pz (beberapa titik nilai 0-900 digambarkan)

Tro, Chemistry: A Molecular Approach 25

mℓ = 0

mℓ = ±1

mℓ = ±1

mℓ = ±2

mℓ = ±2

mℓ = ±3

mℓ = ±3

Friedman, H. G., Choppin, G. R., Feuerbacher, D.G., 1964, “The Shapes of the f orbitals”, J. of Chem. Ed., Vol. 41, No. 7, July, 354-358

4 f

5 d

6 s

1 20 40 60 80 100

n = 1

n = 2

n = 3

n = 4

n = 5

n = 6

n = 7

1s

2p2s

5d5s ; 5p

6p6s

7s ; 7p5f ; 6d

4d ; 4f4s ; 4p

3d3s ; 3p

= f= d= p= s

E n

e r

g y

Atomic Number

binding energy vsatomic number

Day & Selbin, Theoretical Inorganic Chemistry,

1969, p. 96

Detailed Relative Energy of Orbitals in the Quantum Mechanical Model

Note: the relative energy of occupied (n-1)dto ns orbitals

Binding energy of electron with atomic number

(Day & Selbin, Theoretical Inorganic Chemistry, 1969, p. 125 )

37 38 39 40 41

Rb Sr Y Zr Nb

4d

4d

5s

5s 5p

5p

56 57 58 59

Ba La Ce Pr

4f

4f

5d

6s

6s

5d

5,0

10,0

019 20 21 22

K Ca Sc Ti

3d

3d

4s

4s 4p

4p

87 88 89 90 91 92

Fr Ra Ac Th Pa U

5f

5f

6d

7s

7s

6d

Ene

rgy

/ eV

Atomic Number

Very simply the relative energies of the (n-1)d, ns, and np orbitals.

Generally, Zeff increases across the periods WHY?

BUT THE Zeff CHANGE AFFECTS THE (n-1)d-ORBITALS MORE THAN ns and np.

They are closer to the nucleus.

Why only d-electrons?

SPIN ELEKTRON

Lihat media animasi

S

N

SN

SPIN ELEKTRON

dst.

2s 2p

6C: [He] 2s2 2p2 DIAGRAM ORBITAL

2s

2s

2p

2p

(1)

(2)

(3)

(4)

(5)

(6)

(7) (9)(8)

(10) (12)(11)

4s 2 3d 3DIAGRAM ORBITAL

(1)

(3)

(2)

4s 23d 3

4s 2

3d 3 4s 2

3d 3(4)

-2 +2-1 +10 +2 -2+1 -10

(5) (6)

-1 +10

px py pz

+1 -10

px py pz(7) (8)

23V: [Ar] 3d2 4s2

FINDINGS

Various misconseptions in the textbooks and teachers as users

Some examples of misconceptions (Textbooks & Teachers)

??

ORBITAL

?

F A T A L

Hubungan lambang nilai mℓ dengan sumbu Cartes x-y-z

The term of: the LAST electron – The nth electron? ?

Which one to be the last, or the

nth electron??

?

?

?

How does it come to the idea ?

24Cr: [Ar] 3d4 4s2 → [Ar] 3d5 4s1

24Cr: [Ar] 4s2 3d4→ [Ar] 4s1 3d5

?

Which one is the “last electron”?

?

What is “the last electron”?

?

?

?

?

The questions are:What is “the last” electrons of Fe and of Fe2+ ?Are they the same?

What is the electronic configuration of the

neutral atom, Y?

Y: [Ar] 4s2 3d8 !! BAD effect of the slopy aufbau

Keller, R. N., 1962, “Textbook Errors 38: Energy Level Diagrams andExtranuclear Building of the Elements”, Journal of Chemical Education,39, 289-293

Thus the last-two electrons should enter to 4s, and the prior one-two electrons should enter to 3d, resulting in the lowest energy for the whole

ion/atom.

IONISATION ON TRANSITION ELEMENT

AUFBAU PRINCIPLE

Conclusion: The stability of the 3dx or [(n-1)dx]electron is greater than the 4s(1-2) or [ns(1-2)] electron

Thus, ONLY the last electron enter to ns orbital, and the priorone-nine electron(s) should enter to (n-1)d orbital

https://www.youtube.com/watch?v=VQr61aG8LH0

1s2 1s2

2s22s2

3s2 3s23p6 3p6

2p6 2p6

4s2 4s2

3d1

https://www.youtube.com/watch?v=VQr61aG8LH0

https://www.youtube.com/watch?v=VQr61aG8LH0

• Working downwards from the highest energy levels ......

• the valence band (4d, 5s) emission occurs at a binding energy of ca. 0 -8 eV ( measured with respect to the Fermi level, or alternatively at ca. 4 - 12 eV if measured with respect to the vacuum level ).

• the emission from the 4p and 4s levels gives rise to very weak peaks at 54 eV and 88 eV respectively

• the most intense peak at ca. 335 eV is due to emission from the 3dlevels of the Pd atoms, whilst the 3p and 3s levels give rise to the peaks at ca. 534/561 eV and 673 eV respectively.

• the remaining peak is not an XPS peak at all ! - it is an Auger peak arising from x-ray induced Auger emission. It occurs at a kinetic energy of ca. 330 eV (in this case it is really meaningless to refer to an associated binding energy).

• These assignments are summarised below ...

• CONCLUSION:

There are various misconceptions in understanding:

1. The quantum numbers of:

mℓ associated with labeling cartesian orbitals, and “increasing-decreasing” order to the “filling” electrons due to Hund rule

ms associated with unpaired-paired electron(s)

2. The aufbau priciple associated with the ordering energy of orbitals and thus electronic configurations of elements

3. The term of the nth electron

Mn

3d5 4s2 3d5 4s2

3d7

3d7

Co2+

3d5 4s2

Mn Co2+

(A) (B)

3d

4s

3d

4s

Van Quickenborne, et al, J. Chem.Ed. Vol. 71, Number 6, June, 1994, 469-471

ε3d (3dn 4s2) < ε3d (3dn+1 4s1) < ε3d (3dn+2 4s0)

ε4s (3dn 4s2) < ε4s (3dn+1 4s1)

Hasil Penelitian Buku:

A. Bilangan Kuantum• Nomor Sampel Buku: 1. Parning dkk. 2. Johari dkk. 3. Unggul Sudarmo.

4. Michael Purba. 5. Das Salirawati dkk. 6. Tim kreatif, Sukardjo (editor)

Lalu, dimana kemungkinan terjadinya miskonsepsi?

3d

4s

?

?

Conclusion: The stability of the 3dx or [(n-1)dx]electron is greater than the 4s(1-2) or [ns(1-2)] electron

Thus, ONLYthe LASTelectronenter to nsorbital, andthe priorone-nineshould enterto (n-1)dorbital

Don’t worry about the solutions!• Yn,ℓ,m (r,q,f) = Rn,ℓ (r ) . Qℓ,m (q) . Fm (f)

• The essential solutions involving the following values:

(n-ℓ-1)! and (ℓ ± |m| )!

• Thus:

• n and ℓ must be discreet, positive and integer one

• n (ℓ + 1) ; ℓ 0 , and m = ± ℓ( n = 1, 2, 3, 4, 5, …..; ℓ = 0, 1, 2, 3, …..; m = 0, ±1, ± 2, ±3 …..)