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KIMIA (PAI 08128) 2 KIMIA (PAI 08128) 2 SKSSKS
• MATERI KULIAH :1.Struktur atom2.Konfigurasi elektron 3.Sistem Berkala 4.Sifat periodik (potensial ionisasi, jari-jari atom,
afinitas elektron, keelektronegatifan) 5.Teori ikatan kimia6.Struktur molekul7.Sifat gas8.Zat padat dan kisi kristal9.Cairan 10.Asam basa11.Stoikiometri12.Hk. Termodinamika dan Termokimia
MATERIMATERI
Penilaian :Penilaian :
• Kuis : 20 %• Tugas terstruktur : 20 %• Kehadiran : 10 %• UTS : 25 %• UAS : 25 %
Atomic StructureAtomic Structure
Atomic Structure Atomic Structure Atom smallest particle of an element
capable of uncombined existence
Molecule is smallest unit of compound or substance; combination of 2 or more atoms
Contains exceedingly small nucleus with all of the + charge and most of total mass, protons, neutrons
Electrons equal in number to protons, negative charges surround nucleus
Hydrogen simplest ( 1 proton, 1 electron)
Helium next (2 protons, 2 electrons, 2 neutrons)
What are the 3 major parts What are the 3 major parts of an atom?of an atom?
What are the 3 major parts What are the 3 major parts of an atom?of an atom?
• Proton • Neutron • Electron
Draw a diagram showing the Draw a diagram showing the location of each part of the location of each part of the
atom.atom.
Draw a diagram showing the location Draw a diagram showing the location of each part of the atom.of each part of the atom.
http://www.eskom.co.za/nuclear_energy/fuel/fuel.html
Draw a diagram showing the Draw a diagram showing the charges of each part of the charges of each part of the
atom.atom.
Draw a Diagram of an Draw a Diagram of an AtomAtom
Draw a diagram showing the Draw a diagram showing the charges of each part of the atom.charges of each part of the atom.
Describe ProtonDescribe Proton
• Protons are positively charged particles found in the atomic nucleus. Protons were discovered by Ernest Rutherford..
Describe NeutronDescribe Neutron
• Neutrons are uncharged particles found in the atomic nucleus. Neutrons were discovered by James Chadwick in 1932.
Describe ElectronDescribe Electron
Electrons are negatively charged particles that surround the atom's nucleus. Electrons were discovered by J. J. Thomson in 1897.
Electrons determine properties of the atom. Chemical reactions involve sharing or exchanging electrons.
Describe NucleusDescribe Nucleus
The nucleus is the central part of an atom. It is composed of protons and neutrons.
The nucleus contains most of an atom's mass.
It was discovered by Ernest Rutherford in 1911.
Subatomic Particles
Particle Charge Mass (g) Location
Electron (e-) -1 9.11 x 10-28 Electron
cloud
Proton (p+) +1 1.67 x 10-24 Nucleus
Neutron (no) 0 1.67 x 10-24 Nucleus
Complete SymbolsComplete Symbols
• Contain the symbol of the element, the mass number and the atomic number.
X Massnumber
AtomicnumberSubscript →
Superscript →
Atomic NumberAtomic Number
• Atoms are composed of protons, neutrons, and electrons– How then are atoms of one element different
from another element?• Elements are different because they contain
different numbers of PROTONS• The “atomic number” of an element is the
number of protons in the nucleus• # protons in an atom = # electrons
Atomic number (Z) of an element is the number of protons in the nucleus of each atom of that element.
Element # of protons Atomic # (Z)
Carbon 6 6
Phosphorus 15 15
Gold 79 79
Atomic NumberAtomic Number
Mass NumberMass NumberMass number is the number of protons and neutrons in the nucleus of an isotope:
Mass # = pMass # = p++ + n + n00
Nuclide p+ n0 e- Mass #
Oxygen - 10
- 33 42
- 31 15
6 8 1616
Arsenic 75 33 75
Phosphorus 15 3116
EXAMPLE
How many protons, neutrons and electrons are found in an atom of
13355 Cs
Atomic number = protons and electronsThere are 55 protons and 55 electrons
Mass number = sum of protons and neutrons133 – 55 = 78There are 78 neutrons
HHydrogenHydrogen
1
1
Protons: 1Protons: 1Neutrons: 0Neutrons: 0Electrons: 1Electrons: 1
NaSodiuSodiumm
23
11
Protons: 11Protons: 11Neutrons: 12Neutrons: 12Electrons: 11Electrons: 11
– When an atom or molecule gain or loses an electron, it becomes an ion.•A cation has lost an electron and
therefore has a positive charge•An anion has gained an electron and
therefore has a negative charge.
SymbolSymbolAtomic MassAtomic Mass
Atomic NumberAtomic Number
Charge Charge (if ion)(if ion)
Na+
SodiuSodiumm
23
11
Protons: 11Protons: 11Neutrons: 12Neutrons: 12Electrons: 1Electrons: 100
SymbolsSymbols
Find each of these: a) number of protonsb) number of
neutronsc) number of
electronsd) Atomic numbere) Mass Number
Br80 35
If an element has an atomic number of 34 and a mass number of 78, what is the: a) number of protonsb) number of neutronsc) number of electronsd) complete symbol
SymbolsSymbols
If an element has 91 protons and 140 neutrons what is the a) Atomic numberb) Mass numberc) number of electronsd) complete symbol
SymbolsSymbols
If an element has 78 electrons and 117 neutrons what is the a) Atomic numberb) Mass numberc) number of protonsd) complete symbol
SymbolsSymbols
RheniumRhenium
Re186
75
Rhenium isotopeRhenium isotope
Re187
75
Isotop adalah atom-atom yang mempunyai nomor atom sama, tetapi nomor massanya berbeda.
– Contoh : ,
Isobar adalah atom-atom yang mempunyai nomor atom berbeda, tetapi nomor massanya sama.
– Contoh :
Isoton adalah atom-atom yang mempunyai nomor atom berbeda, tetapi jumlah neutronnnya sama.
– Contoh :
C126 C13
6
N146 N14
7
C136 N14
7
• Contoh soal– Tentukan jumlah proton dan neutron dalam
isotop-isotop berikut ini:
Mgdan Na,Na, N, N, C, C, H, H, , H 2412
2411
2311
157
147
146
126
31
21
11