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PARTIKEL DASAR
PENYUSUN ATOM
MODEL ATOM
NOMOR ATOM
NOMOR MASSA
ISOTOP, ISOBAR
ISOTON
KONFIGURASI
ELEKTRON
STRUKTUR ATOM

Hal.: 4 Isi dengan Judul Halaman Terkait
THE ATOMIC THEORY
ATOMIC THEORY
DEMOCRITUS
THOMSON
DALTON
RUTHERFORD
NIELS BOHR
MODERN

Hal.: 5
DEMOCRITUS (460 -370 SM)
The tiny particles could not be divided to
any further estent are called ATOMS

A. MODEL ATOM JOHN DALTON
TEORI YG DIKEMUKAKAN :
1. atom adalah bagian terkecil suatu unsur
2. atom digambarkan sebagai bola pejal yg
sangat kecil, suatu unsur memiliki atom2 yg
identik dan berbeda untuk unsur yg berbeda
3. atom2 bergabung membentuk senyawa
dengan perbandingan bilangan bulat dan
sederhana
4. Reaksi kimia meruipakan pemisahan atau
penggabungan atau penyusunan kembali dari
atom2, sehingga atom tidak dapat
dimusnahkan atau diciptakan
Model atom
Dalton, seperti

B. THOMSON’S ATOMIC MODEL
Thomson proposed an atomic model called RAISIN
PLUM PUDDING MODEL
Thomson described atom as a positively charged
sphere containing several negatively charged particles
called ELECTRONS. The electrons are scattered in
the sphere like raisins in a plum pudding

C. MODEL ATOM RUTHERFORD
1.Atom adalah bola berongga yg
tersusun dari inti atom dan elektron
yg mengelilinginya.
2.Inti atom bermuatan positif dan
massa atom terpusat pada inti atom
MODEL TATA
SURYA

D. NIELS BOHR’S ATOMIC MODEL
AND MODERN’S ATOMIC MODEL
Membebaskan
Energi
Elektron
Elektron
Menyerap
Energi
Inti
Atom
Niels Bohr succeeded in overcoming the weakness
of the Rutherford’s atomic model

Hal.: 10 Isi dengan Judul
.Model atom menurut Niels Bohr, 1913:
1. Atom terdiri dari inti yg bermuatan positif
dan dikelilingi elektron yg bermuatan
negatif di dalam suatu lintasan
2. Elektron dapat berpindah dari satu lintasan
ke lintasan yg lain dengan menyerap atau
memancarkan energi sehingga energi
elektron atom itu tidak akan berkurang
3. Jika elektron berpindah lintasan ke lintasan
yg lebih tinggi, maka elektron akan
menyerap energi. Jika elektron berpindah
ke lintasan yg lebih rendah akan
memancarkan energi

DEVELOPMENT OF ATOMS MODELS
Dalton
(1803)
Thomson
(1897)
Rutherford
(1910)
Model atom
Niels Bohr
(1913)
Mekanika
Kuantum
(1926)

MECANICA QUANTUM THEORY
 Erwin Schrodinger, 1927, mengelurkan teori mekanika
kuantum atau mekanika gelombang.
Kulit-kulit elektron bukan merupakan kedudukan yg pasti dari
suatu elektron, tetapi hanyalah suatu kebolehjadian saja.
Dengan demikian kedudukan dan kecepatan gerakan
elektron dalam atom berada di ruang tertentu dalam atom
disebut ORBITAL

A. Partikel dasar :
partikel-partikel pembentuk atom yang terdiri dari proton, elektron dan
neutron.
1. Proton
partikel pembentuk atom yang mempunyai massa sma dengan satu sma (amu)
dan bermuatan +
2. Elektron
partikel pembentuk atom yang tidak mempunyai massa dan bermuatan -
3. Neutron
partikel pembentuk atom yang bermassa satu sma (amu) dan netral.
B. Nukleus
Inti atom yang bermuatan positif, terdiri dari proton dan neutron.
PARTIKEL DASAR PENYUSUN ATOM

1. Discovery of the Electron
In 1897, J.J. Thomson used a cathode ray tube to
deduce the presence of a negatively charged
particle: the electron
Nilai hasil pengukuran Thomson tentang rasio
antara muatan elektron (e) dan massa elektron m
adalah : e/m = -1,7588196. 1011
C/kg

Mass of the Electron
1916 – Robert Millikan determines the mass
of the electron: 1/1840 the mass of a
hydrogen atom (me = 9,1093897 . 10-31
kg)
The oil drop apparatus
Mass of the
electron is
9.11 x 10-28
g
,l

PENEMUAN PROTON
Jika massa elektron = 0, berarti suatu partikel tdk
mempunyai massa.padahal partikel materi
mempunyai massa yg dapat diukur.Jadi
bagaimana mungkin atom bersifat netral dan
mempunyai massa jika hanya ada elektron saja di
dlm atom?????
GOLDSTEIN melakukan eksperimen
menggunakan tabung gas yg memiliki katode.
Ternyata pada saat terbentuk elektron yg menuju
anode, terbentuk pula sinar positif yg menuju arah
berlawanan melewati lubang katode

RUTHERFORD’S EXPERIMENT
A beam of alfa particles is directed towards the thin
gold plate through alfa slit in the lead plate.
Alpha particles that pass the empty space
Go straight through.
Alpha particles that approach
the nucleus are deflected.
Alpha particles that hit the
nucleus are bounced back
nucleon
electron

Rutherford berhasil mengukur massa inti atom yg
kira-kira dua kali dari massa proton dalam inti.
Sehingga, menurut Rutherford harus ada partikel
lain di dalam inti atom dan partikel tersebut tidak
bermuatan.
Baru pada tahun 1932, J.CHADWICK menemukan
NEUTRON dari penembakan berilium
menggunakan partikel2 alfa dan kemu dian
neutron ini diketahui sebagau partikel penyusun
inti atom
Neutron merupakan partikel tidak bermuatan
dengan massa kira-kira 1,67 x 10-27
kg

PARTICLE OF ATOM
ATOM
NUCLEUS
OUT OF
NUCLEUS
PROTON
NEUTRON
ELEKTRON
POSITIVE CHARGE
Massa 1 proton = 1,6726486 x 10-24
gram = 1 sma
Muatan 1 proton = + 1 = +1,6 x 10-19
C
NO CHARGE
Massa 1 neutron = 1,6749544 x10-24
gram = 1 sma
NEGATIVE CHARGE
Massa 1 elektron = 9,1093897 x 10-28
gram =
1/ 1840 sma
Muatan 1 elektron = - 1 = - 1,6 x 10-19
C

ATOM SYMBOL
Atom hidrogen
dengan satu proton dan elektron
dan tidak memiliki netron.

Notasi unsur : Z
A
X
dengan
X : tanda atom (unsur)
Z : nomor atom = jumlah elektron (e)
= jumlah proton (p)
A : bilangan massa = jumlah proton +
neutron
‘’Pada atom netral, berlaku: jumlah
elektron = jumlah proton’’

CONTOH SOAL
1. Tentukan jumlah elektron, proton den neutron dari
unsur 26
56
Fe !
Jawab :
Jumlah elektron = jumlah proton = nomor atom = 26
Jumlah neutron = bilangan massa - nomor atom = 56 - 26 = 30
2. Berikan notasi unsur X, jika diketahui jumlah
neutron = 14 dan jumlah elektron = 13 !
Jawab :
Nomor atom = jumlah elektron = 13
Bilangan massa = jumlah proton + neutron = 13 + 14 = 27
Jadi notasi unsurnya : 13
27
X

ISOTOP, ISOBAR, ISOTON
ISOTOP
Atom-atom dari unsur yang sama mempunyai
massa yang berbeda
Contoh : C12
, C13
, C14
ISOBAR
Atom-atom dari unsur yang berbeda mempunyai
massa yang sama.
Contoh : 6 C14
dan 7 N14
, 11Na24
dan 12 Mg24
ISOTON
Atom-atom dari unsur yang berbeda mempunyai
jumlah neutron yang sama.
Contoh : 6C13
dan 7N14
, 15 P31
dan 16 S 32

ELECTRON CONFIGURATION
 The arrangement of electrons in atom shells is
known as electron configuration.
 Every shells contain a number of electrons follow
the formula : 2 n 2
.
shell K (n =1) = 2 x 12
= 2 elektron
Shell L (n =2) = 2 x 22
= 8 elektron
Shell M (n =3) = 2 x 32
= 18 elektron
Shell N (n =4) = 2 x 42
= 32 elektron
Shell O (n =5) = 2 x 52
= 50 elektron

DETERMINE ELECTRONS CONFIGURATION
K L M N
11Na : 2 8 8 1
12Mg : 2 8 8 2
13Al : 2 8 3
35Br : 2 8 18 7
Valensi electrons
are used to form
chemical bonds

THE MAIN QUANTUM NUMBER (N)
The Main Quantum Number (n)
are the number of electron in every
level of energy (2n2
) with n is the
main quantum number
Quantum number for
Shell K ---- n = 1 Shell M ---- n = 3
Shell L ---- n = 2 Shell N ---- n = 4

AZIMUT QUANTUM NUMBER (l )
 Indicate form and positition of orbital as probability of
electron arrangement and show the sub level of energy.
 Azimut quantum number follow equal l = n – 1
 Azimut quantum number have value from 0 to n – 1
main azimut sub level of energy
quantumquantum (the place of electron)
number number
n = 1 --- l = 0 s (sharp)
n = 2 --- l = 1 p (principle)
n = 3 --- l = 2 d (diffuse)
n = 4 --- l = 3 f (fundamental)

MAGNETIC QUANTUM NUMBER (m)
Indicate the orientation of orbital in space
of atom.
Follow this equal --> m = (-l, + l)
Example for l = 1
m begin from -1, 0 , + 1

SPIN NUMBER (s)
Describe the characteristic of electron that
rotate in their axis
produces two different of direction or
spin : + ½ dan – ½
s2
Px Py Pz

The Electron Configuration
Pauli
 Two electron in an atom are imposible to
have the same four quantum number.
Aufbau
 Electrons in an atom fill orbitals with low
level of energy and followed to orbital with
high level of energy.
1s < 2s < 2p < 3s < 3p < 4s < 3d < 4p < 5s < 4d <
5p < 6s < 5d < 4f < 6p < 7s < 6d < 5f,

TINGKAT ENERGI DALAM ATOM

The example for determine electron
configuration
Atom with atomic number = 11
11 Na = 1s2
2s2
2p6
3s1

The elements periodic system
• Elements were grouped based on similar
properties.Later, they were based on similar
properties and increasing atomic mass.
• This led to the arrangement of elements in a
periodic system.
• In modern periodic system, elements are
arranged based on increase of atomic number
and similar properties.

The classification of elements
Classification of elements
Metals
And
Non metals
Dobereiner’s
Triads
System
Newlands’
Law
Octaves
Mendeleev’s
Periodic
system
Modern’s
periodic
system
Lavoisier Johan
Wolfgang
A.R.Newland Dmitry
Ivanovich
Mendeleev
Henry G.
Moseley

Dobereiner’s Triads
 Grouped elements based on similar properties in groups of three
called triads. In a triad, the properties of the second element are
in between the properties of the first and third elements.
Ca
Sr
Ba
Li
K
Na

Newland’s law of Oktaves
 Classified elements in the increasing order
of their atomic masses.
 Because the repeating trend always occurs
in sets of eight, the system is known as the
Law of Octaves.
1. H 2. Li 3. Be 4. B 5. C 6. N 7. O
8.F 9. Na 10.Mg 11.Al 12.Si 13.P 14.S
15.Cl 16.K 17.Ca 18.Cr 19.Ti 20.Mn 21.Fe
22.Co 23.Cu 24.Zn 25.Y 26.In 27.As 28.Se

Mendeleev’s periodic system
He arranged the elements based on the
increasing atomic mass horizontally
forming rows called periods.
Elements with similar properties will form
column called groups.

The modern periodic system
In the modern periodic system,
elements are classified based on the
increasing atomic number (Z) which
is the characteristic for every
element.
The arrangement of elements based
on the increasing atomic number and
similarities in properties.
Produces a repetition of properties of
element in the form of periods (rows)
and columns.

 The elements of A groups are called the main
group elements.
 Those of B groups are the transition elements.
 The elements in the two long rows below the
main table are known as inner transition
elements, the first row is named the lanthanide
series and the second row is the actinide series.

 Group 1 A : alkali metals.
(except Hidrogen)
 Group II A : alkaline earth metals.
 Group VIIA: halogens
 Group VIII A : noble gases
Transition metals
Are groups between II A and III A
consist of
less reactive metals.

Periodic Properties of the Elements
 Atomic radius
is the distance from the nucleus to the outermost
shell.
 The atomic radius decreases across a period.
 The atomic radius increases down a group.
 Ionization Energy (IE)
is defined as the energy required to remove an
electron of a gaseous atom or ion.
 The ionization energy increases across a period
 The ionization energy decreases down a group.

 Electron affinity
is the energy involved when a gaseous atom
or ion receives one electron to form a
negative ion.
 The electron affinity tends to increase across
a periode.
 The electron affinity tends to decrease down
a group
 Electronegativity
is measure of the ability of an atom to attract
electrons in a chemical bond.
 The electronegativity increases across a
period.
 The electronegativity decreases down a
group.

Melting Points and Boiling Points
is the temperature at which the vapor
pressure of a solid is the same as the
vapor pressure of its liquid.
 In one period, the melting points and boiling
points initially increase until group IVA, then
decrease and reach the lowest level at
group VIIIA
 In one group, the melting points and boiling
points of metals decrease while those of
nonmetals increase.

REFERENCES
Zulfikar, Kimia Kesehatan untuk SMK,
Jilid 1, Direktorat Pembinaan SMK,
Depdiknas,2008.
Michael Purba, KIMIA, untuk SMA
kelas X, Erlangga,2006
J.M.C.Johari,M.Rachmawati,Chemistry
for Senior High School Grade X,
English Edition,Esis,2009

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