Post on 17-Mar-2020
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The Components of MatterChapter 2
Element, Atom, Compound, and Molecule
CHEMICAL ELEMENTS - pure substances that cannot be decomposed by ordinary means to other substances.
An ATOM is the smallest particle of an element that has the chemical properties of the element. c e ca p ope t es o t e e e e t.
CHEMICAL COMPOUNDS are composed of two or more kinds of atoms and so can be decomposed to those atoms.
A MOLECULE is the smallest unit of a compound that retains the chemical characteristics of the compound.
Elements, Compounds, and MixturesMolecule: two or more atoms join together chemically. Example: H2, H2O, CO2, C6H6, O2, Cl2, C2H6O
Compound: Molecule that contains at least two different elements.
Example: H2O, CO2, C6H6, C2H6O
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Sample Problem
Postulates of Dalton’s Atomic Theory (1808)
All matter is made of atoms
All atoms of a given element are identical
Compounds are formed by a combination of two or more p ydifferent kinds of atoms
A chemical reaction is arrangement of atoms present in the reacting substances
Atoms are indivisible and indestructible. Atoms cannot be created or converted to other atom types
Three Laws
1. Mass Conservation: Total mass of substances does not change in a reaction
180 g of glucose +
192 g of oxygen gas
264 g of carbon dioxide +
108 g of water
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Three Laws
2. Definite Composition: The components of a compound is the same irrespective of the source of the compound
Calcium Carbonate: Made up of calcium, oxygen, and carbon in constant proportion of mass
i.e. 40% calcium, 12% carbon and 48% oxygen
Three Laws
3. Multiple Proportion: If A and B reacts to form two compounds, the masses of B that combines with a fixed mass of A in the two compounds can be expressed as a ratio of small whole number
Consider two compounds
Carbon oxide I Carbon oxide II--------------------------------------------------------------------
g of oxygen/100 g compound 57.1 72.7g of carbon/100 g compound 42.9 27.3
g of oxygen/g of carbon 1.33 2.66
Ratio of ‘g of oxygen/g of carbong of oxygen/g of carbon’ in compound II and compound I is “2”
Electricity and Radioactivity
Objects can bear an electric chargeTwo types of charges- positive and negativeSubatomic particles?
Marie Curie suggested that atoms of certain substances emit rays when they disintegrate. (1898)These are radioactive materials like uranium, polonium, radium.
Contradicted Dolton’s idea that atoms are indivisible
234U → 230Th + 4He92 90 2
(alpha-ray)
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Evidence for Sub-atomic ParticlesThomson experiments with Cathode-Ray Tubes (1897)
Discovery of The Electrons
Cathode rays: beam of negatively charged particle known as electrons
By balancing the effects of the electrical and magnetic fields, the charge/mass (e/m) ratio was determined for the electronelectron
Same charge/mass ratio in experiments using 20 different metals as cathodes and several different gasses
Electrons are present in atoms of all elements!!
Millikan’s Oil Drop Experiment Determination of Charge of an Electron
By balancing the electrostatic attractive and gravitation forces,electron charge (-1.60 x 10-19C) was determined. From e and e/m values, electron mass was calculated (9.109388 x 10-28g)
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In 1886, Goldstein, using equipment similar to cathode ray tube, discovered particles with charge equal and opposite to that of electron, but much larger mass
Rutherford later (1911) found these particles to be identical
Evidence for Sub-atomic Particles
to hydrogen atoms minus one electron
Chadwick (1932) discovered particle with similar mass to proton but zero charge
Named these particles protons
Neutron
Properties of Subatomic Particles
Subatomic Particle
Location in Atom
Symbol Mass (grams) Relative Mass
Relative Charge
neutron nucleus n0 1.674927 x 10-24 1 0
proton nucleus p+ 1.672622 x 10-24 1 +1
electron Moving around
outside the nucleus
e- 9.109383 x 10-28 1/1836 -1
Evidence for the nucleus
Three subatomic particles: electron, proton and neutron
How these particles are arranged in an atom?
Thomson’s model of atomic structure: “plum pudding” or “chocolate chip cookie” model
Atoms consisted of negatively charged electrons embedded in a cloud of positive chargeThe negative and positive charges balance and result in the atom being neutral
--
-
-
--
++
+
+
+
+
Electron
Positive charge
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Evidence for The Nucleus
In 1911, Geiger and Rutherford studied the interaction of positively charged particles (α-particles) with thin metal foils
If the “plum pudding” hypothesis (model) were true, what would happen to α-particles fired at a metal foil?
--
-
-
--
++
+
+
+
+
Electron
Positive charge
Scattering of α-particles
Scattering of α-particlesObservation…..
“It was about as credible as if you fired a 15-inch shell at a piece of paper and it came back and hit you.” Ernest Rutherford
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Scattering of α -particles
Rutherford’s hypothesis:Positive charge concentrated in one tiny region called the nucleus(now known to be about 10-15 m in diameter)Electrons were thought to be distributed throughout the remainder of the atom (10-10 m in diameter)
Inside the Atom
Rutherford also noted that not all the mass of the atom was accounted for by the protons
Chadwick’s neutron
Rutherford proposed a solar system-like model for the yatom
Properties of Subatomic Particles
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Inside the Atom
Review:Protons and neutrons contribute nearly all the mass
Protons and neutrons are tightly bound together in the nucleusRadius of nucleus is only 10-5 that of the atomVolume is only 10-15 than of the entire atom
Electrons surround the nucleus as a large “cloud” of negative charge density
Most of the atom’s volume is occupied by electrons
But how are these electrons really arranged around the nucleus?
Atomic and Mass Numbers
Atomic number = The number of protons in the nucleus of an element
Symbolized by the letter Z
Mass number = The total number of protons and neutrons in the
nucleus
Symbolized by the letter A
X is element symbol
A
Atomic and Mass Numbers
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Na11
23
A Sodium (Na) atom has 11 protons and 12 neutrons. What is the symbol for a sodium atom?
Identify the atomic number, mass number, and number of neutrons of
Atomic and Mass Numbers
Identify the atomic number, mass number, and number of neutrons of the following elements:
Z A Number of neutronsC6
12
2963 Cu
82207Pb
IsotopesIndividual atoms have a defined number of protons, electrons and neutrons
What are isotopes?
Atoms of the same element with the same atomic numberbut different mass numbers.
Same number of protons but different number of neutrons
Isotopes
Each element has a characteristic number (and relative abundance) of isotopes
Phosphorus (P) has one naturally occurring isotope with 16 neutrons
C b (C) h h 6 (98 93%
P3115
Also known as phosphorus-31
Carbon (C) has two isotopes, one has 6 neutrons (98.93% abundant), the other has 7 neutrons (1.07% abundant)
Chlorine (Cl) has two isotopes18 neutrons (75.53%)20 neutrons (24.47%)
C126 C13
6Also known as carbon-12
Also known as carbon-13
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Relative Masses
The mass of an atom cannot be determined by simply adding up the mass of its constituent protons, neutrons and electrons
Some mass is converted to energy, which is used to hold the nucleus together (binding energy)
d ff l d h h ll b d b d h It is difficult to predict how much mass will be used to bind the nucleus together
Fortunately, the atomic mass of each element can be determined experimentally using very sensitive instruments (mass spectrometer)
Mass Spectrometer
http://www.youtube.com/watch?v=J-wao0O0_qM
Relative MassesFor example the mass of a 12C atom is measured to be 1.9926 x 10-23 g
An exceedingly small number!!!!!!!!!
Rather than work with awkwardly small numbers, atomic masses are converted into more easily handled units
Conversion unit is called the atomic mass unit, μ, μ
By convention, the atomic mass unit is equal to 1/12 the mass of a 12C atom
(1/12)(1.9926 x 10-23g) = 1 μ = 1.6605 x 10-24 gThe atomic mass of 12C is exactly 12 μ
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Some Basic Concepts
Atomic MassRelative
Absolute Atomic Mass Mass of a C-atom1.9926 x 10-23 g
12 μ
Converting to bigger Converting to bigger numbersnumbers
Atomic Weight
Mole
12.011
12.011g
Taking contributions Taking contributions of many isotopes of many isotopes and averaging them and averaging them
Amount in grams Amount in grams numerically equal to its numerically equal to its atomic weightatomic weight
Some Basic Concepts1. For the number
of neutrons a. 31b. 15c. 16
P3115
2. The measured atomic mass of a 31P atom is 5.1433 x 10-23 g The converted relative mass is
a. 8.5404 x 10–47
b. 3.2285 x 10–2
c 30 974
1μ = 1.6605 x 10-24 g
d. 46 c. 30.974
3. 1 mole of Phosphorous is a. 8.5404 x 10–47 g
b. 3.2285 x 10–2g
c. 30.974g
1 mole = amount in grams numerically equal to its atomic weight
Atomic Weight
For elements with more than one isotope, the atomic weightreported in the periodic table represents a weighted average of the atomic masses of the naturally occurring isotopes
In other words, it’s the weight of an average atom
For example:3535Cl (75.53 % abundance) has atomic mass = 34.97μ37Cl (24.47 % abundance) has atomic mass = 36.97μ
Atomic weight =
μμμ 35.45100
).97(24.47)(36).97(75.53)(34=
+
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Some Basic Concepts
Magnesium: 24Mg (78.99%); 23.9850 μ25Mg (10.00%); 24.9858 μ26Mg (11.01%); 25.9826 μ
3. The atomic weight of magnesium a. 24.3060b. 23.9999c. 24.1096d. 24.9858e. 24.0000
Concept of Mole
How many atoms will be there?Will there be equal number of atoms in all of them?
Concept of Avogadro’s Number
1 mole of any substances will have same number of particles
The magic number is 6.023 ×1023
1 mole of Ca
1 mole of water
6.023 ×1023 6.023 ×1023
1 mole of photons
6.023 ×1023
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Concept of Mole
Different mass and volume but each contains 6.022 x 1023 atoms
Mass, Mole, and Atom Conversions
Moles x = gramsgrams
1 molGrams x = moles1 mol
grams
Molar mass of Aluminum = 27.0 g/mol. Determine the mass
of 0.35 mol of Al.
Mass, Mole, and Atom Conversions
Determine the number of moles of Tin in 36.5 g Tin. Molar mass of Tin = 117.7 g/mol.
Determine the number of atoms in 36.5 g Tin.
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Periodic Table of the Elements1 IA
2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 VIIIA
1 H
1.008
IIA
IIIA
IVA
VA
VIA
VIIA
2 He4.003
3 Li
6.941
4 Be 9.012
5 B
10.81
6 C
12.011
7 N
14.007
8 O
15.999
9 F
18.998
10 Ne20.179
11 Na 22.990
12 Mg 24.305
IIIB
IVB
VB
VIB
VIIB
[------VIIIB------]
IB
IIB
13 Al
26.982
14 Si
28.086
15 P
30.974
16 S
32.06
17 Cl
35.453
18 Ar
39.94819 K
39 098
20 Ca 40 08
21 Sc
44 956
22 Ti
47 90
23 V
50 942
24 Cr
51 996
25 Mn 54 938
26 Fe
55 847
27 Co 58 933
28 Ni 58 70
29 Cu 63 546
30 Zn 65 38
31 Ga 69 72
32 Ge 72 59
33 As 74 922
34 Se 78 96
35 Br
79 904
36 Kr 83 8039.098 40.08 44.956 47.90 50.942 51.996 54.938 55.847 58.933 58.70 63.546 65.38 69.72 72.59 74.922 78.96 79.904 83.80
37 Rb 85.468
38 Sr 87.62
39 Y
88.906
40 Zr 91.22
41 Nb 92.906
42 Mo 95.94
43 Tc (98)
44 Ru 101.07
45 Rh 102.91
46 Pd 106.4
47 Ag 107.87
48 Cd 112.41
49 In
114.82
50 Sn 118.69
51 Sb 121.75
52 Te
127.60
53 I
126.90
54 Xe
131.3055 Cs 132.91
56 Ba 137.33
57# La
138.91
72 Hf
178.49
73 Ta
180.95
74 W
183.85
75 Re 186.21
76 Os 190.2
77 Ir
192.22
78 Pt
195.09
79 Au 196.97
80 Hg 200.59
81 Tl
204.37
82 Pb 207.2
83 Bi
200.98
84 Po(209)
85 At (210)
86 Rn(222)
87 Fr (223)
88 Ra 226.03
89† Ac 227.03
104 Rf (261)
105 Db (262)
106 Sg (263)
107 Bh (262)
108 Hs (265)
109 Mt (268)
DLC 1o/97
# 58 Ce 140.12
59 Pr
140.91
60 Nd 144.24
61 Pm (145)
62 Sm 150.4
63 Eu 151.96
64 Gd 157.25
65 Tb
158.93
66 Dy 162.50
67 Ho 164.93
68 Er
167.26
69 Tm168.93
70 Yb173.04
71 Lu
174.97
† 90 Th
232.04
91 Pa
231.04
92 U
238.03
93 Np 237.05
94 Pu (244)
95 Am (243)
96 Cm (247)
97 Bk (247)
98 Cf (251)
99 Es (252)
100 Fm (257)
101 Md(258)
102 No(259)
103 Lr (260)
The Periodic Table
Ne
He
8A
Groups: the columns in the periodic table
Elements in the same group have similar chemical properties
Kr
Xe
Rn
Ar
CaK Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Periods: the rows in the periodic table
p
H
Li Be
Na Mg
CaK Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Ar
Ne
He
F
ClSPSiAl
B C N O
1A
2A
3B 4B 5B 6B 7B 8B 8B 8B 1B 2B
3A 4A 5A 6A 7A
8AAlkali Metals
Rb
Cs
Fr Ra
Ba
Sr XeITeSbSnInCdAgPdRhRuTcMoNbZrY
La
Ac Rf
Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Db Sg Bh Hs Mt
LuYbTmErHoDyTbGdEuSmPmNdPrCe
Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr
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H
Li Be
Na Mg
CaK Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Ar
Ne
He
F
ClSPSiAl
B C N O
1A
2A
3B 4B 5B 6B 7B 8B 8B 8B 1B 2B
3A 4A 5A 6A 7A
8AAlkaline Earth Metals
Rb
Cs
Fr Ra
Ba
Sr XeITeSbSnInCdAgPdRhRuTcMoNbZrY
La
Ac Rf
Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Db Sg Bh Hs Mt
LuYbTmErHoDyTbGdEuSmPmNdPrCe
Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr
H
Li Be
Na Mg
CaK Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Ar
Ne
He
F
ClSPSiAl
B C N O
1A
2A
3B 4B 5B 6B 7B 8B 8B 8B 1B 2B
3A 4A 5A 6A 7A
8AHalogens
Rb
Cs
Fr Ra
Ba
Sr XeITeSbSnInCdAgPdRhRuTcMoNbZrY
La
Ac Rf
Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Db Sg Bh Hs Mt
LuYbTmErHoDyTbGdEuSmPmNdPrCe
Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr
H
Li Be
Na Mg
CaK Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Ar
Ne
He
F
ClSPSiAl
B C N O
1A
2A
3B 4B 5B 6B 7B 8B 8B 8B 1B 2B
3A 4A 5A 6A 7A
8ANoble Gases
Rb
Cs
Fr Ra
Ba
Sr XeITeSbSnInCdAgPdRhRuTcMoNbZrY
La
Ac Rf
Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Db Sg Bh Hs Mt
LuYbTmErHoDyTbGdEuSmPmNdPrCe
Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr
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Metals, nonmetals and metalloids1 IA
2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 VIIIA
1 H
1.008
IIA
IIIA
IVA
VA
VIA
VIIA
2 He4.003
3 Li
6.941
4 Be 9.012
5 B
10.81
6 C
12.011
7 N
14.007
8 O
15.999
9 F
18.998
10 Ne20.179
11 Na 22.990
12 Mg 24.305
IIIB
IVB
VB
VIB
VIIB
[------VIIIB------]
IB
IIB
13 Al
26.982
14 Si
28.086
15 P
30.974
16 S
32.06
17 Cl
35.453
18 Ar
39.94819 K
39.098
20 Ca 40.08
21 Sc
44.956
22 Ti
47.90
23 V
50.942
24 Cr
51.996
25 Mn 54.938
26 Fe
55.847
27 Co 58.933
28 Ni 58.70
29 Cu 63.546
30 Zn 65.38
31 Ga 69.72
32 Ge 72.59
33 As 74.922
34 Se 78.96
35 Br
79.904
36 Kr 83.80
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 5437 Rb 85.468
38 Sr 87.62
39 Y
88.906
40 Zr 91.22
41 Nb 92.906
42 Mo 95.94
43 Tc (98)
44 Ru 101.07
45 Rh 102.91
46Pd 106.4
47 Ag 107.87
48 Cd 112.41
49 In
114.82
50 Sn 118.69
51 Sb 121.75
52Te
127.60
53I
126.90
54Xe
131.3055 Cs 132.91
56 Ba 137.33
57# La
138.91
72 Hf
178.49
73 Ta
180.95
74 W
183.85
75 Re 186.21
76 Os 190.2
77 Ir
192.22
78 Pt
195.09
79 Au 196.97
80 Hg 200.59
81 Tl
204.37
82 Pb 207.2
83 Bi
200.98
84 Po(209)
85 At (210)
86 Rn(222)
87 Fr (223)
88 Ra 226.03
89† Ac 227.03
104 Rf (261)
105 Db (262)
106 Sg (263)
107 Bh (262)
108 Hs (265)
109 Mt (268)
DLC 1o/97
# 58 Ce 140.12
59 Pr
140.91
60 Nd 144.24
61 Pm (145)
62 Sm 150.4
63 Eu 151.96
64 Gd 157.25
65 Tb
158.93
66 Dy 162.50
67 Ho 164.93
68 Er
167.26
69 Tm168.93
70 Yb173.04
71 Lu
174.97
† 90 Th
232.04
91 Pa
231.04
92 U
238.03
93 Np 237.05
94 Pu (244)
95 Am (243)
96 Cm (247)
97 Bk (247)
98 Cf (251)
99 Es (252)
100 Fm (257)
101 Md(258)
102 No(259)
103 Lr (260)
Nonmetals
Metals
Metalloids
Metals
• Left side of the periodic table– except H
• Properties:• Properties:– lustrous (shiny)
– good thermal and electrical conductors
– malleable
– solids at RT • except Hg = liquid
Non-Metals
• Right side of table– plus H
• Properties:• Properties:– Dull appearance
– Brittle when solids
– Do not conduct heat or electricity well
– Primarily solids or gases at RT• Bromine = liquid
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Metalloids
• Stair step between metals and non-metals
• Properties in between metals and non-metalsProperties in between metals and non metals– Si: brittle but semi-conductor
H
Li Be
Na Mg
CaK Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Ar
Ne
He
F
ClSPSiAl
B C N O
1A
2A
3B 4B 5B 6B 7B 8B 8B 8B 1B 2B
3A 4A 5A 6A 7A
8AMain Group or Representative
Elements
Rb
Cs
Fr Ra
Ba
Sr XeITeSbSnInCdAgPdRhRuTcMoNbZrY
La
Ac Rf
Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Db Sg Bh Hs Mt
LuYbTmErHoDyTbGdEuSmPmNdPrCe
Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr
H
Li Be
Na Mg
CaK Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Ar
Ne
He
F
ClSPSiAl
B C N O
1A
2A
3B 4B 5B 6B 7B 8B 8B 8B 1B 2B
3A 4A 5A 6A 7A
8ATransition Metals
Rb
Cs
Fr Ra
Ba
Sr XeITeSbSnInCdAgPdRhRuTcMoNbZrY
La
Ac Rf
Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Db Sg Bh Hs Mt
LuYbTmErHoDyTbGdEuSmPmNdPrCe
Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr
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H
Li Be
Na Mg
CaK Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Ar
Ne
He
F
ClSPSiAl
B C N O
1A
2A
3B 4B 5B 6B 7B 8B 8B 8B 1B 2B
3A 4A 5A 6A 7A
8ALanthanide Series
Rb
Cs
Fr Ra
Ba
Sr XeITeSbSnInCdAgPdRhRuTcMoNbZrY
La
Ac Rf
Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Db Sg Bh Hs Mt
LuYbTmErHoDyTbGdEuSmPmNdPrCe
Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr
H
Li Be
Na Mg
CaK Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Ar
Ne
He
F
ClSPSiAl
B C N O
1A
2A
3B 4B 5B 6B 7B 8B 8B 8B 1B 2B
3A 4A 5A 6A 7A
8A
Actinide Series
Rb
Cs
Fr Ra
Ba
Sr XeITeSbSnInCdAgPdRhRuTcMoNbZrY
La
Ac Rf
Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Db Sg Bh Hs Mt
LuYbTmErHoDyTbGdEuSmPmNdPrCe
Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr
The Periodic Table
Terminology of Periodic Table
Periods: Horizontal rows
Groups: Vertical columns
Main group elements: 1A - 8AGroup 1A: Alkali metal family
fGroup 2A: Alkaline earth metal familyGroup 7A: Halogen FamilyGroup 8A: Noble gas family
Transition metals or elements: 1B - 8B
Lanthanides: elements 58 – 71
Actinides: elements 90 – 103
Metals, nonmetals and metalloids
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We know where the protons and neutrons are located in an atom. But how are electrons really arranged around the nucleus?
Laws of mass1. Law of mass conservation: the total mass of substances does
not change during a chemical reaction.
“Matter cannot be created or destroyed”
Laws of mass2. Law of definitive composition: no matter what its source, a
particular compound is composed of the same elements in the same parts (fractions) by mass.
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Calculating the mass of an element in a compound
Laws of massLaw of multiple proportions: if elements A and B react to form two compounds, the different masses of B that combine with a fixed mass of A can be expressed as ratio of small whole number.
Example: Formation of CO and CO2Example: Formation of CO and CO2
Inside the Atom
Review:
Three elementary particles: proton, electron and neutron
Protons contribute all the positive charge
Electrons contribute all the negative charge
Neutral atoms have net charge of zero, thus an equal number of protons g , q pand electrons
Protons and neutrons contribute nearly all the mass
Protons and neutrons are tightly bound together in the nucleus
Electrons surround the nucleus as a large “cloud” of negative charge
density
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The atomic notation of Silver is
109
Ag47
• Draw the diagram showing the arrangement of protons, neutrons d l t i il t and electrons in a silver atom.
• Draw the diagram showing the result of alpha-particle scattering experiment using silver foil.
Mole Concept
MoleOne mole is the amount of a substance that contains as many elementary entities (atoms, molecules, or other particles) as there are in exactly 12 g of carbon-12 isotope.
1 mole contains Avogadro's number of elementary entities.
Avogadro’s number: 6 02214155 x 1023 particles Avogadro s number: 6.02214155 x 10 particles
Molar massThe mass in grams of one mole of any element (6.022 x 1023 atoms of that element).
Units: grams per mole (g/mol).
An element’s molar mass is the amount in grams numerically equal to its atomic weight.
Mass, Mole, and Atom Conversions
Determine the number of gallium (Ga) atoms present in 52.0 g of gallium.
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Atomic and Mass Numbers
Symbol 65Cu 86Kr _______ ______
# of protons _____ _____ 78 ______
# of neutrons _____ ______ 117 46
# of electrons ______ ______ ____ 36
Name of the Element _____________ ______ ________
Symbol 65Cu 86Kr 195Pt 82Kr
# of protons 29 36 78 36
# of neutrons 36 50 117 46
Atomic and Mass Numbers
# of electrons 29 36 78 36
Name of the copper Krypton Platinum Krypton
Element
The atomic notation of Silver is
109
Ag47
• Draw the diagram showing the arrangement of protons, neutrons d l t i il t and electrons in a silver atom.
• Draw the diagram showing the result of alpha-particle scattering experiment using silver foil.
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Three Kinds of Radiation
Alpha (α), beta (β), and gamma (γ)
Radiation Electric chargeα +2β -1γ 0