Download - Struktur Atom 2014
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Partikel ini berada dalam gerakan yang
konstan, tetapi dapat bergabung
membentuk suatu kombinasi yang mantap.
Potongan paling kecil dari materi yang tidakbisa dibagi lagi disebut atom
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Melibatkan kejadian kimia
Berdasarkan asumsinya pada data
kuantitatif
Ditunjang oleh 2 percobaan ( 2 hukum alam)
Hukum kekekalan massa
Hukum perbandingan tetap
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Using the Law of Conservat ion of Mass
You heat 2.53 g of metallic mercury in air, which produces 2.73 g of a red-orange residue. Assume that the chemical change is the reaction of the
metal with oxygen in air.
Mercury + oxygen red-orange residue
What is the mass of oxygen that reacts?
When you strongly heat the red-orange residue, it
decomposes to give back mercury and releases the
oxygen, which you collect.
What is the mass of oxygen you collect?
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Jumlah massa zat-zat yang ada sebelumreaksi sama dengan jumlah massa zat-zat yang ada setelah reaksi
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Percobaan ke
:
Sebelum
pemanasan (g
Mg)
Setelah
pemanasan (g
MgO)
Perbandingan
Mg/MgO
1 0.62 1.02 0.61
2 0.48 0.79 0.60
3 0.36 0.60 0.60
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Setiap senyawa tersusun dari unsur-unsur
tertentu dengan perbandingan tetap
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Tiap-tiap unsur kimia tersusun dari partikel-partikel kecilyang tidak bisa dihancurkan dan dibagi yang disebut atom.Selama perubahan kimia, atom tidak bisa diciptakan dandimusnahkan.
Semua atom dari suatu unsur mempunyai massa dan sifatyang sama, tetapi atom-atom dari suatu unsur berbedadengan atom-atom dari unsur lain, baik masa maupun sifat-sifatnya.
Dalam senyawa kimia, atom-atom dari unsur yang berlainanmelakukan ikatan dengan perbandingan numerik yangsama, exs. 1 atom A dengan 2 atom B (AB2)
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8 X2Y16 X 8 Y+
2.1
Law of _________________________________
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Adanya awan yang bermuatan positif dengansejumlah elektron yang terpusat yang cukup untukmenetralkan.
However, if there are electrons (-), there must be a +component.
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2.2
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1. atoms positive charge is concentrated in the nucleus
2. proton (p) has opposite (+) charge of electron
3. mass of p is 1840 x mass of e-(1.67 x 10-24g)
particle velocity ~ 1.4 x 107m/s
(~5% speed of light)
(1908 Nobel Prize in Chemistry)
2.2
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Sebagian besar masa dan semua muatan positif terpusat
pada daerah yang sempit yang disebut inti atom nuklei)
Sebagian besar atom merupakan ruang kosong
Besarnya muatan pada inti berbeda untuk atom yang
berbeda, kira-kira setengah dari nilai numerik dari bobot
atom suatu unsur
Di luar inti suatu atom harus terdapat elektron yang
jumlahnya sama dengan satuan muatan inti
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atomic radius ~ 100 pm = 1 x 10-10m
nuclear radius ~ 5 x 10-3pm = 5 x 10-15m
Rutherfords Model of
the Atom
2.2
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H atoms - 1 p; He atoms - 2 p
mass He/mass H should = 2
measured mass He/mass H = 4
+9
Be1
n +12
C + energy
neutron (n) is neutral (charge = 0)
n mass ~ p mass = 1.67 x 10-24g
2.2
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ParticleMass
(g)Charge
(Coulombs)Charge(units)
Electron (e-) 9.1 x 10
-28 -1.6 x 10
-19 -1
Proton (p) 1.67 x 10-24
+1.6 x 10-19
+1
Neutron (n) 1.67 x 10-24
0 0
mass p = mass n = 1840 x mass e-
2.2
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ParticleMass
(g)Charge
(Coulombs)Charge(units)
Electron (e-) 9.1 x 10
-28 -1.6 x 10
-19 -1
Proton (p) 1.67 x 10-24
+1.6 x 10-19
+1
Neutron (n) 1.67 x 10-24
0 0
mass p = mass n = 1840 x mass e-
2.2
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The Atom
Nucleus Electron
Shell or Orbit
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The Atom Hydrogen
Proton Electron
Hydrogen has one proton, one electron and NO neutrons
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The Atom Helium
ElectronProton
Neutron
Helium has two electrons, two protons and two neutrons
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The Atom Helium
ElectronProton
Neutron
Helium has two electrons, two protons and two neutrons
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The Atom Lithium
Protons
Neutrons
Electrons
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The Atom Beryllium
Protons
Neutrons
Electrons
Beryllium has four electrons, four protons and five neutrons.
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The Atom Boron
Protons
Neutrons
Electrons
Boron has five electrons, five protons and six neutrons.
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The Atom Carbon
Protons
Neutrons
Electrons
Carbon has six electrons, six protons and six neutrons.
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The Atom Nitrogen
Protons
Neutrons
Electrons
Nitrogen has seven electrons, seven protons and seven neutrons.
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The Atom Oxygen
Protons
Neutrons
Electrons
Oxygen has eight electrons, eight protons and eight neutrons.
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The Atom Fluorine
Protons
Neutrons
Electrons
Fluorine has nine electrons, nine protons and ten neutrons.
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The Atom Neon
Protons
Neutrons
Electrons
Neon has ten electrons, ten protons and ten neutrons.
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The Atom Sodium
Protons
Neutrons
Electrons
Sodium has eleven electrons, eleven protons and twelve neutrons.
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_______________(Z) = number of protons in nucleus
______________(A) = number of protons + number of neutrons
= atomic number (Z) + number of neutrons
___________are atoms of the same element (X) with different
numbers of neutrons in the nucleus
XA
Z
H11 H (D)
21 H (T)
31
U23592 U23892
Mass Number
Atomic NumberElement Symbol
2.3
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2.3
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Menentukan perbandingan muatan terhadap massa (e/m)dari ion positif yang dihasilkan dalam sebuah tabung sinar
kanal
Dalam gas neon biasa kira-kira 91% dari atom-atom
mempunyai massa normal dan 9% dari atom-atom
tersebut 22/20 lebih berat dari normal.
KESIMPULAN
Atom-atom dari unsur yang sama dapat sedikit berbeda
dalam massanya
SOTOP
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Symbols
Find each of these:a) number of protons
b) number of neutrons
c) number of electrons
d) Atomic number
e) Mass Number
symbol Cl
name Chlorine
atomic number 17
mass number 35.453
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An____is formed when an atom, or group of atoms, has a net positive or
negative charge (why?).
_____ion with a positive charge
If a neutral atom_______one or more electrons
it becomes a cation.
_____ion with a negative charge
If a neutral atom_______one or more electrons
it becomes an anion.
Na 11 protons11 electrons Na+ 11 protons
10 electrons
Cl 17 protons
17 electronsCl-
17 protons
18 electrons
2.5
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PeriodG
roup
Alkali
Metal
Noble
Gas
Ha
logen
AlkaliEarth
Metal
2.4
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Naturally occurring carbon consists of three isotopes, 12C, 13C,and 14C. State the number of protons, neutrons, and electrons
in each of these carbon atoms.12C 13C 14C
6 6 6
#p _______ _______ _______
#n_______ _______ _______
#e _______ _______ _______
LecturePLUS Timberlake 38
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12C 13C 14C
6 6 6
#p __6___ _ 6___ ___6___
#n __6___ _ _7___ ___8___
#e __6___ _ 6___ ___6___
LecturePLUS Timberlake 39
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Listed on the periodic table
Gives the mass of average atom of each
element compared to 12C
Average atom based on all the isotopesand their abundance %
LecturePLUS Timberlake 40
Na22.99
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Percent(%) abundance of isotopes
Mass of each isotope of that element
Weighted average =mass isotope1(%) + mass isotope2(%) +
100 100
LecturePLUS Timberlake 41
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Isotopes Mass of Isotope Abundance24Mg = 24.0 amu 78.70%
25Mg = 25.0 amu 10.13%
26Mg = 26.0 amu 11.17%
Atomic mass (average mass) Mg = 24.3 amu
LecturePLUS Timberlake 42
Mg24.3
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Gallium is a metallic element found in
small lasers used in compact discplayers. In a sample of gallium, there is
60.2% of gallium-69 (68.9 amu) atoms and
39.8% of gallium-71 (70.9 amu) atoms.What is the atomic mass of gallium?
LecturePLUS Timberlake 43
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Ga-69
68.9 amu x 60.2 = 41.5 amu for 69Ga
100
Ga-71 (%/100)70.9 amu x 39.8 = 28.2 amu for 71Ga
100
Atomic mass Ga = 69.7 amu
LecturePLUS Timberlake 44
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A sample of boron consists of 10B (mass10.0 amu) and 11B (mass 11.0 amu). If theaverage atomic mass of B is 10.8 amu,
what is the % abundance of each boronisotope?
LecturePLUS Timberlake 45
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Assign X and Y values:
X = % 10B Y = % 11B
Determine Y in terms of X
X + Y = 100Y = 100 - X
Solve for X:
X (10.0) + (100 - X )(11.0) = 10.8100 100
Multiply through by 100
10.0 X + 1100 - 11.0X = 1080
LecturePLUS Timberlake 46
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Collect X terms
10.0 X - 11.0 X = 1080 - 1100
- 1.0 X = -20
X = -20 = 20 %10
B- 1.0
Y = 100 - X
% 11B = 100 - 20% = 80% 11B
LecturePLUS Timberlake 47
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Copper has two isotopes 63Cu (62.9 amu)and 65Cu (64.9 amu). What is the %abundance of each isotope? (Hint:Check periodic table for atomic mass)