Simposium Kimia (Indonesia ~ English)

1. PENGENALAN DASAR STRUKTUR
ATOM
BASIC INTRODUCTION TO
ATOMIC STRUCTURE

2. ATOM IS THE
BASIC UNIT OF
MATTER COMPOSED
OF ATOMIC
NUCLEUS AND
NEGATIVELY
CHARGED
ELECTRONS
SURROUNDING IT.
The picture above is the picture
of atomic structure

3. Developing of Atomic Theory and
Model
Bohr’s
Democritus’ Rutherford’s The modern
John Dalton’s J.J Thomson’s Atomic
Atomic Atomic Theory View of Atomic
Atomic Theory Atomic Theory Theory and
Theory and and Model Theory and
and Model and Model Model
Model Model

4. 1. DEMOCRITUS’ ATOMIC THEORY
AND MODEL
Democritus, an ancient Greek’s philosopher
who lived from 460 BC to 370 BC, has
developed a matter composing theory.
According to Democritus, if a stone divided
and we did it repeatedly until it is undivided
any more, every pieces of that stone had the
same character with its origin. He labeled the
smallest piece of a stone as atomos (A=
no, TOMos= divided), which mean “invisible”.
Based on his theory, every atom that
constructed different matter is dissimilar.

5. 2. JOHN DALTON’S ATOMIC THEORY
AND MODEL
Even though Democritus named the
technical terminology of atom, but the
concept of atom as the smallest
particle was published by John Dalton
in 1803. John Dalton explained the
model based on his calculation data
while observing chemical reactions.
Dalton suggested as followed
a. Atom is the smallest particle of
matter
b. Atom is small sized and round
shaped, indivisible, neither created
nor destroyed.
c. All atoms of given elements are
identical
d. Atoms of different elements can be
joined to produce substance with
fixed scale
e. Atoms combine to make
compound; a given compound always
has the same relative number and
kind of atoms

6. 3. J.J THOMSON’S ATOMIC THEORY
AND MODEL
Dalton’s suggestion about
atom as the smallest particle was
broken after the discovery of
electron by Thomson. In 1897, J.J
Thomson did an experiment using
cathode ray tube.

7. Atomic model by Thomson

8. 4. RUTHERFORD’S ATOMIC THEORY AND
MODEL
In almost the same time
with Thomson’s
experiment, four
physicists, Henry
Becquerel, Marie
Curie, Pierre Curie, and
Ernest Rutherford, had
research with radioactivity.
There were three kind of
radioactive beams, alpha
particle (α) was positively
charge, beta particle (β)
was negatively charge, and
gamma particle (γ) was
zero particle. The study of
radioactivity gave a
breakthrough to Rutherford
for making his atomic
model and theory.

9. 5. BOHR’S ATOMIC THEORY AND
MODEL

10. 6. THE MODERN VIEW OF ATOMIC
THEORY AND MODEL
The incapability of Bohr’s theory in
explaining atomic model aside from
Hydrogen and the influence of
magnetic field was accomplished in
1924 by Louis de Broglie. According to
Broglie, beside as a particle, electron
cam be defined as wave, whilst Bohr
had assumed that electron was only
defined as particle. This suggestion
was improved by Erwin Schrodinger
and Werner Heisenberg which
generate the modern atomic
model, known as mechanical quantum
theory. The main principle of this theory
is the electron motion in surrounding
the nucleus performs characteristic of
wave. The mechanical theory is used
to explain atom and molecule behavior.

11. DEVELOPMENT OF CHEMICAL ELEMENTS
PERIODICAL SYSTEM

12. 1. LAVOISIER ELEMENTS
CLASSIFICATION METHOD
Lavoisier Chemical Elements Classification
Group Gas Non-metal Metal Soil
Light Sulfur Antimo Gold Iron Calcium
Group Calor Fosfor n Timbel Silve Magnesium
Membe Oxyge Chloride Arsen Zinc r Barit
rs n acid Cobalt Mercu Nickel Alumina
Nitro Fluoride Lead ry Platin silica
gen acid Mangan Bismut um
Hydro Borax molibd h Tungs
gen acid enum Coppe ten
Boric r

13. 2. Dobereiner Elements Classification
Method
Triad 1 Triad 2 Triad 3 Triad 4
(Alkalin Metal) (Earth Alkalin) (Halogen) (Group VI)
Lithium 7 Calcium40,08 Chlorin35,45 Sulfur32,06
Sodium 23 Stronsium87,62 Bromine79,91 Selenium78,96
Potassium Barium137,34 Iodine 126,90 Telurium127,60
39

14. 3. CHANCOURTOIS ELEMENTS
CLASSIFICATION METHOD
In 1862, a France geologist, Alexander Beguyer de Chancourtois, classified
chemical elements based on its atomic weight raising. These chemical elements
were developed into spiral shaped arrangement
Atomic weight = 7 + 16n; n=
element sequence

15. 4. NEWLAND’S ELEMENTS
CLASSIFICATION METHOD
H F 8 Cl 15 Co/Ni Br Pd I 43 Pt/Ir
1 22 29 36 50
Li 2 Na 9 K 16 Cu Rb Ag Cs Tl
23 30 37 44 51
G 3 Mg Ca Zn Sr Cd Ba/V Pb
10 17 24 31 38 45 52
Be 4 Al 11 Cr Y Ce/L U Ta Th
18 25 e 32 39 46 53
C 5 Si 12 Ti 19 In Zr Sn W Hg 54
26 33 40 47
N 6 P 13 Mn As Di/M Sb Nb Bi 55
20 27 o 34 41 48
O 7 S 14 Fe Se Ro/R Te Au Os 56
21 28 u 35 42 49

16. 5. MENDELEEV’S ELEMENTS
CLASSIFICATION METHOD

17. MEYER’S PERIODIC TABLE

18. 6. MOSELEY’S ELEMENTS
CLASSIFICATION METHOD
In 1909 and 1911, Ernest Rutherford found one of the base particles inside the
atom, that is proton, and the nucleus. According to Rutherford, atom is acompiled
of positively charged atomic nucleus surrounded by negatively electrons in circle.
If a metal is shot with high energy electron, X-ray will be emitted.
Base on Rutherford’s findings, Henry Moseley studied X-ray and its correlation
with the amount of electrical charge using X-ray spectroscopy. Then, he plotted
the X-ray frequence with the increasing of atomic number. The results show linear
trend that revealed the correlation between atomic number and atomic properties
periodically. After that, Moseley arranged the elements based on the increasing of
atomic number in the periodic table form.

19. 7. SEABORG’S ELEMENTS
CLASSIFICATION METHOD
In 1940, Glenn Seaborg discovered trans-
uranium, the elements with atomic number of 94-
102. This finding triggered some difficulties
concerning the trans-uranium elements position
in periodic table. This problem is finally solved by
composing new rows ang generally changed the
modern periodic table.

21. Atom’s Basic
Particle

22. 1. ELECTRON
Cathode ray tube experiment was first performed William Crookes
(1875). The results of his experiment was the discovery of a beam
emerging from the cathode to the anode is called the cathode. George
Johnstone Stoney (1891) which provides a cathode ray called
"electrons". The weakness of Stoney could not explain the notion of
atoms in an element have the same properties while different elements
will have different properties, although both have electrons. Antoine
Henri Becquerel (1896) determine the rays emitted from radioactive
elements in nature similar to the electron. Joseph John Thomson (1897)
William Crookes experiment continued influence of the electric field and
magnetic fields in cathode ray tube.

23. 2. Proton
If 0 is the electron mass a particle has no mass when the
particle has a mass of material that can be measured. So did
the fact that the atom was neutral. How could it be neutral
atoms and have, if there are only electrons in atoms?
Eugene Goldstein (1886) conducted experiments of gas
cylinders which have a cathode, the holes were and given an
electric charge. It turned out that the electrons formed at the
anode to the positive rays are formed that led to the opposite
direction through the hole at the cathode. After the various
gases tested in this tube, hydrogen is the gas that produces
light of the positive charge of both the smallest mass or load, so
that these particles called protons. Proton mass = 1 sma
(atomic mass units) and the proton charge = +1

24. 4. NEUTRON
Prediction of W. Rutherford Bothe and H. Becker (1930)
conducted experiments on alpha particle bombardment
nuclei of beryllium (Be). It turned out that the particle
radiation produced a high penetrating power. The
experiment was continued by James Chadwick (1932). It
turned out that the radiation particles that cause the high
penetrating power is neutral or no charge and its mass is
almost equal to the proton. These particles called
neutrons.

25. CALCULATE THE AMOUNT OF
PROTON, ELECTRON, AND NEUTRON OF ATOM
X = Atom or elements symbol
A = mass number = total proton and neutron
Z = atomic number = amount of proton
Proton and electron have opposite charge. If the total amount of proton
and electron is the same, the atom will have zero charge. But if the total
amount of proton and electron is different, then atom will charge either
positive or negative. Charged atom is called ion. Positive ion is named
cation and negative ion is named anion.

26. THE ELECTRON STRUCTURE OF ATOM
(ELECTRON CONFIGURATION)
Atomic Electron Configuration of Atomic number within 1-20
Atomic Electron’s number Valence Atomic Electron’s number Valence
Elements Electrons Elements Electrons
K L M N K L M N
1He 1 1 11Na 2 8 1 1
2He 2 2 12Mg 2 8 2 2
3Li 2 1 1 13Al 2 8 3 3
4Be 2 2 2 14Si 2 8 4 4
5B 2 3 3 15P 2 8 5 5
6C 2 4 4 16S 2 8 6 6
7N 2 5 5 17Cl 2 8 7 7
8O 2 6 6 18Ar 2 8 8 8
9F 2 7 7 19K 2 8 8 1 1
10Ne 2 8 8 20Ca 2 8 8 2 2

27. CORRELATION OF ELECTRON CONFIGURATION
WITH PERIOD AND GROUP
The electron configuration of atom can be used to determine an atom
position in periodic table. The group number is determined from the
number of its valence electron. While the period number is obtained from
the total number of shell filled with electron.
Group Number = valence electron
Period Number = number of
shell filled with electrons

28. THE ATOMIC RELATIVE MASS OF ELEMENTS
In the beginning, hydrogen was used as standard. Then after that,
oxygen began to be used as standard, substitusing hydrogen. In 1961,
carbon was used a standard. Atomic mass (in grams) has a very small
value. Therefore, scientist agreed to label atomic mass unit (amu) as
standard mass for atom. The value of 1 amu is equal to 1/12 of one
atomic mass of C-12.
1 amu = 1/12 x 1 atomic mass of C-12 = 1/12 x 1.99268 x 10-23 gram =
1.66 x 10-24 gram

29. CATEGORIZING ELEMENTS INTO ISOTOPE,
ISOBAR AND ISOTON

30. 1. ISOTOPE
Isotopes are atoms that have the same atomic
number but have different mass numbers. Each
isotope of an element have the same chemical
properties because the same number of valence
electrons
Example :

31. 2. ISOBAR
Isobar is the elements that have different atomic
numbers but the same mass number.
Example:

32. 3. ISOTON
Atoms are different but have the same number of neutrons.
Example:

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