chapter 2 the structure of the atom
TRANSCRIPT
CHAPTER 2CHAPTER 2
2.1 MATTER Most of the things that we could see in this world are MATTER
What is matter?Matter means: - anything that occupies space & has mass
- made up of tiny & discrete particles
- Exist as element @ compound Next
A pure substance which cannot be broken down into simpler substance physically & chemically
Matter
Usually made up of two or more elements which are chemically
bonded together
Matter
1.Matter are made up of tiny & discrete particles
2. Size of particles are very minute ~~ 1x 10-7cm
3. Consist of atoms, molecules ions
Next
Let’s see the particles in bromine liquid
Particle theory
The smallest particle of an element and not breakable anymore.
Examples:
Atom of hydrogen
atom of magnesium
atom of oxygen
atom of chlorine
H
Mg
Cl
O
Particle theory
A group of two @ more atoms, which might consist of: one type of element (Element)
@ different types of element (Compound)
Examples of element molecules:
Molecule of hydrogen gas
Molecule of oxygen gas
Molecule of chlorine gasOO
Cl Cl
HH
Examples of compound molecules:
Molecule of water, H2O
Molecule of ammonia, NH3
Molecule of ethanol, C2H5OH
HH
O
H
H
H NO
C CH
H
H
HH
HParticle theory
Ions are atoms which have charge
Positively-charged ion /cation (loss
e-)
Negatively charged ion / anion (gain
e-)
+
-
Hydrogen atom
Hydrogen ion
Magnesium atom Magnesium
ion
Oxygen atom Oxide ion
Chlorine atom Chlorine
ion
Particle theory
H+
HLose electron
Mg2
+
Lose electronMg
O2
-
Gain electronO
Cl-
Gain electronCl
Symbol of element
Examples of ions:
• Kinetic means motion (move)• Kinetic theory states that:
1. Matter consist of particles which constantly moving
2. particles move in random motion , collide with each other
A. substance is cooled, - particles lose kinetic energy - move slower
B. substance is heated, - particles gain kinetic
energy- move faster
Heat energy makes particles move faster!!!
Experiment which supports the kinetic
theory:Investigating the diffusion of
particles in a solid, liquid and gas
What is diffusion ?What is diffusion ?
How diffusion supports How diffusion supports the the kinetic theorykinetic theory ? ?
Diffusion happens anyway that different concentration
of particles
Is the rate of diffusion different in solid, liquid,
and gas state?
Let’s get an experiment to check it out!!!
Diffusion in Solid (membrane)
Diffusion in Liquid ( )
Diffusion in Gas (air)
The conclusion is…….
• Diffusion happens in solid, liquid, and gas states
• Diffusion occurs slowest in solid, faster in liquid and fastest in gas
• Diffusion occurs faster in subtance with lower density
• Diffusion supports kinetic energy
The Physical States of Matter
Solid
Liquid
Gas
The Shape & Volume of Particles
The Physical Changes of Matter
Freezing
GasLiquid
Solid
MeltingSublimatio
n
Boiling
Condensation
Sublimation
Determine the Melting Point of Naphthalene
Melting point – the temperature
which a solid becomes liquid
Diagram of heating naphthalene
Q1-Q4 Q5-Q7
Solid naphthalene
Water
Heating curve of naphthalene
A
CB
D
Temperature / ˚C
Time / minute
79˚C
Q1-Q4 Q5-Q7
What is the Melting point?A: 79˚C
What is the physical state at B-C?A: solid and liquid
Where is point that Melting process started?A: B
Where is point that Melting process ended?A: C
graph apparatus
Why the curve of heating has no change at B-C?A: because the heat energy absorbed by naphthalene molecules to overcome the forces of attraction to becomes liquid
Why solid naphthalene heated in water ?A: to ensure a uniform heating
If the melting point of Substance X is 123˚C, can we still use water as medium? Why?A: No. Because its melting point is higher than the boiling point of water. We can use oil bath to replace water. graph apparatusPhysical changes
Determine the Freezing Point of Naphthalene
Freezing point – the temperature which a solution
becomes solid
Cooling curve of naphthalene
Q1-Q4 Q5-Q7
79˚C
E
Temperature / ˚C
G
H
Time / minute
F
Is the freezing point same with the Melting point?A: Yes, both are 79˚C
What is the physical state change in this experiment?A: Liquid naphthalene changes to solid
Where is the point that freezing process started?A: F
Where is the point that freezing process ended?A: G
Why the curve of heating has no change at F-G?A: because the heat energy released during formation of bonds is equal to the heat released to surroundings
Why liquid naphthalene in the boiling tube is cooled inside a conical flask?A: to ensure a uniform cooling
Different solution has different boiling point & freezing point
Diagram of cooling naphthalene
Q1-Q4 Q5-Q7
Liquid naphthalene
Empty conical flask
2.2 ATOMIC STRUCTURE
The Historical Development Of Atomic Models
• John Dalton – imagine atom as a indivisible tiny ball
• J.J. Thomson – discovered electrons• Ernest Rutherford – discovered proton,
mass of atom concentrated in nucleus• Neils Bohr – proposed the electrons
move in shells around the nucleus• James Chadwick – proved the existence
of neutrons
Subatomic Particle In An Atom
Subatomic Particle In An Atom
Proton
Neutron
Electron
Subatomic Particle In An Atom
Proton Electron
Neutron
Nucleus of atom Electron
shells
Subatomic Particle In An Atom
Subatomic Particle In An Atom
Subatomic Particle In An Atom
PROPERTIES PROTON NEUTRON ELECTRON
Symbol
Electric Charge
Relative Mass
Location
Subatomic Particle In An Atom
PROPERTIES PROTON NEUTRON ELECTRON
Symbol p
Electric Charge
Relative Mass
Location
Subatomic Particle In An Atom
PROPERTIES PROTON NEUTRON ELECTRON
Symbol p n
Electric Charge
Relative Mass
Location
Subatomic Particle In An Atom
PROPERTIES PROTON NEUTRON ELECTRON
Symbol p n e-
Electric Charge
Relative Mass
Location
Subatomic Particle In An Atom
PROPERTIES PROTON NEUTRON ELECTRON
Symbol p n e-
Electric Charge
+1
Relative Mass
Location
Subatomic Particle In An Atom
PROPERTIES PROTON NEUTRON ELECTRON
Symbol p n e-
Electric Charge
+1 0
Relative Mass
Location
Subatomic Particle In An Atom
PROPERTIES PROTON NEUTRON ELECTRON
Symbol p n e-
Electric Charge
+1 0 -1
Relative Mass
Location
Subatomic Particle In An Atom
PROPERTIES PROTON NEUTRON ELECTRON
Symbol p n e-
Electric Charge
+1 0 -1
Relative Mass 1
Location
Subatomic Particle In An Atom
PROPERTIES PROTON NEUTRON ELECTRON
Symbol p n e-
Electric Charge
+1 0 -1
Relative Mass 1 1
Location
Subatomic Particle In An Atom
PROPERTIES PROTON NEUTRON ELECTRON
Symbol p n e-
Electric Charge
+1 0 -1
Relative Mass 1 1 1/1240 ≈ 0
Location
Subatomic Particle In An Atom
PROPERTIES PROTON NEUTRON ELECTRON
Symbol p n e-
Electric Charge
+1 0 -1
Relative Mass 1 1 1/1240 ≈ 0
Location in the nucleus
atom
Subatomic Particle In An Atom
PROPERTIES PROTON NEUTRON ELECTRON
Symbol p n e-
Electric Charge
+1 0 -1
Relative Mass 1 1 1/1240 ≈ 0
Location in the nucleus
atom
in the nucleus
atom
Subatomic Particle In An Atom
PROPERTIES PROTON NEUTRON ELECTRON
Symbol p n e-
Electric Charge
+1 0 -1
Relative Mass 1 1 1/1240 ≈ 0
Location in the nucleus
atom
in the nucleus
atom
Electron shells which around the
nucleus atom
40
20Ca
Nucleon number
Proton number
Symbol of Element
-When an atom is neutral , (1.refer ions)
its number of proton = e-
- number of protons = 20 so number of elecrons = 20- 2.electron configuration = 2.8.8.2 valence electron = 2
Symbol of element
3.Next
Electron Configuration
Also known as electron arrangement
How electrons fill into the shells?
Helium HeProton number 2
2
Hydrogen HProton number 1
1
Lithium LiProton number 3
2 . 1
Beryllium BeProton number 4
2 . 2
Boron Bproton number 5
2 . 3
Carbon CProton number 6
2 . 4
Nitrogen NProton number 7
2 . 5
Oxygen OProton number 8
2 . 6
Fluorine FProton number 9
2 . 7
Neon NeProton number 10
2 . 8
Sodium NaProton number 11
2 . 8 . 1
Magnesium MgProton number 12
2 . 8 . 2
Aluminium AlProton number 13
2 . 8 . 3
Silicon SiProton number 14
2 . 8 . 4
Phosphorus PProton number 15
2 . 8 . 5
Sulphur SProton number 16
2 . 8 . 6
Chlorine ClProton number 17
2 . 8 . 7
Argon ArProton number 18
2 . 8 . 8
Potassium KProton number 19
2 . 8 . 8 . 1
Calcium CaProton number 20
2 . 8 . 8 . 2
Conclusion:Conclusion:
1st Shell: max 1st Shell: max 22 e- e-2nd Shell: max 2nd Shell: max 88 e- e-3rd Shell: max 3rd Shell: max 88 e- e-
ARRANGEMENT OF SHELLS IN AN ATOM
NUCLEUS
2 ELECTRONS
8 ELECTRONS
8 ELECTRONS
18 ELECTRONS
1
23
4
Electron arrangement in the carbon atom
C12
6
proton number = 6
number of protons = 6
number of electrons = 6
2 . 4
= electron
nucleus
Number of valence electrons = 4
23
11Na
2 . 8 . 1
number of protons = 11
proton number = 11
number of electrons = 11
= electron
Nucleus
Number of valence electrons = 1 Symbol of element
Try to draw out the electron
arrangement in shells
Draw & state the electron arrangement of the elements below
X15
7Y
24
12Z
39
19
Let us learn some chemical words !!
• Proton number (p) – number of protons in the nucleus of atom
• Nucleon number (p+n)–total number of protons and neutrons in the nucleus of atom
3. Valence electron –the electrons in the outermost shell
4. Electron configuration –arrangement of electron
Repeat them !!Proton number number of protons in the nucleus of
atom
Nucleon numbertotal number of protons and nucleons
in the nucleus of atom
Valence electron the electrons in the outermost shell
Electron configuration –arrangement of electron
Try this out!!!
Elements
ProtonNumber
NucleonNumber
Number of
Neutrons
A 3 7
B 6 12
C 19 10
D 16 16
E 17 18
F 40 20
Q1 Fill in the blanks
Elements
ProtonNumber
NucleonNumber
Number of
Neutrons
A 3 7 4
B 6 12 6
C 9 19 10
D 16 32 16
E 17 35 18
F 20 40 20
Q1 Answers
Elements
Number of
Neutron
Nucleon
Number
Number of
electrons
ElectronConfiguratio
n
A 5 9
B 8 2.6
C 19 2.7
D 14 2.8.3
E 32 16
F 20 40
Q2 Fill in the blanks
Elements
Number of
Neutron
Nucleon
Number
Number of
electrons
ElectronConfiguratio
n
A 5 9 4 2.2
B 8 16 8 2.6
C 10 19 9 2.7
D 14 27 13 2.8.3
E 16 32 16 2.8.6
F 20 40 20 2.8.8.2
Q2 Answers
2.3 ISOTOPES
• Isotopes is just like twins, same genetic but different of DNA
• atoms of the same element with same number of protons but different number of neutrons
What is isotopes?
Examples of Isotopes
• Take a look at Wikipedia isotopes table
• Hydrogen :
• Graphite :
• Oxygen :
1
1
H 3
1
H2
1
H
12
6
C 14
6
C13
6
C
16
8
O18
8
O17
8
O
Isotopes of Hydrogen
Hydrogen :
1
1
H
2
1
H
3
1
H
Properties of isotopesOxygen
Isotopes
No of proton
No of neutron
No of e-
e- configuration
Valence e-
16
8
O18
8
O17
8
O
Properties of isotopes
Oxygen Isotopes
No of proton 8
No of neutron
No of e-
e- configuration
Valence e-
16
8
O18
8
O17
8
O
Properties of isotopes
Oxygen Isotopes
No of proton 8 8
No of neutron
No of e-
e- configuration
Valence e-
16
8
O18
8
O17
8
O
Properties of isotopes
Oxygen Isotopes
No of proton 8 8 8
No of neutron
No of e-
e- configuration
Valence e-
16
8
O18
8
O17
8
O
Properties of isotopes
Oxygen Isotopes
No of proton 16 16 16
No of neutron 16
No of e-
e- configuration
Valence e-
16
8
O18
8
O17
8
O
Properties of isotopes
Oxygen Isotopes
No of proton 16 16 16
No of neutron 16 17
No of e-
e- configuration
Valence e-
16
8
O18
8
O17
8
O
Properties of isotopes
Oxygen Isotopes
No of proton 16 16 16
No of neutron 16 17 18
No of e-
e- configuration
Valence e-
16
8
O18
8
O17
8
O
Properties of isotopes
Oxygen Isotopes
No of proton 16 16 16
No of neutron 16 17 18
No of e- 16
e- configuration
Valence e-
16
8
O18
8
O17
8
O
Properties of isotopes
Oxygen Isotopes
No of proton 16 16 16
No of neutron 16 17 18
No of e- 16 16
e- configuration
Valence e-
16
8
O18
8
O17
8
O
Properties of isotopes
Oxygen Isotopes
No of proton 16 16 16
No of neutron 16 17 18
No of e- 16 16 16
e- configuration
Valence e-
16
8
O18
8
O17
8
O
Properties of isotopes
Oxygen Isotopes
No of proton 16 16 16
No of neutron 16 17 18
No of e- 16 16 16
e- configuration 2.8.6
Valence e-
16
8
O18
8
O17
8
O
Properties of isotopes
Oxygen Isotopes
No of proton 16 16 16
No of neutron 16 17 18
No of e- 16 16 16
e- configuration 2.8.6 2.8.6
Valence e-
16
8
O18
8
O17
8
O
Properties of isotopes
Oxygen Isotopes
No of proton 16 16 16
No of neutron 16 17 18
No of e- 16 16 16
e- configuration 2.8.6 2.8.6 2.8.6
Valence e-
16
8
O18
8
O17
8
O
Properties of isotopes
Oxygen Isotopes
No of proton 16 16 16
No of neutron 16 17 18
No of e- 16 16 16
e- configuration 2.8.6 2.8.6 2.8.6
Valence e- 6
16
8
O18
8
O17
8
O
Properties of isotopes
Oxygen Isotopes
No of proton 16 16 16
No of neutron 16 17 18
No of e- 16 16 16
e- configuration 2.8.6 2.8.6 2.8.6
Valence e- 6 6
16
8
O18
8
O17
8
O
Properties of isotopes
Oxygen Isotopes
No of proton 16 16 16
No of neutron 16 17 18
No of e- 16 16 16
e- configuration 2.8.6 2.8.6 2.8.6
Valence e- 6 6 6
16
8
O18
8
O17
8
O
Conclusion:
• Number of valence electron are same
• The chemical properties also same
• The physical properties might be same, might be different
Try this out!!!
Elements Proton Number Nucleon Number
P 3 7
Q 9 19
R 16 32
S 15 31
T 16 33
U 18 40
Q3. Answer the structure questions
a ) What means proton number?
A: The numbers of proton in the nucleus of an atom
b) What means nucleon number?
A: The numbers of proton & neutron in the nucleus
of an atom
c) Write the electron arrangement for element Q.
A: 2.7
d) How many valence electrons that element Q has?
A: 7
e) How many electron shells that element Q has?
A: two
40
18
U
f) Which pair of elements are isotopes? Explain.
A: R & T. Because they have same proton number but different nucleon number
g) Is R&T have same chemical properties? Why?
A: Yes. Because they have same valence electron
h) How many protons, neutrons, and electrons are
there in atom S?
A: 15 protons, 16 neutrons and 15 electrons
i) Write the symbol to represent atom U. A: 40
18
U
