Download Matter, Atoms, & Periodic Table

Matter, Atoms, & Periodic
Table
Matter
• Has a mass and volume.
• Has chemical properties and the ability to
change into another substance as the
result of a chemical or physical change.
• Atoms make up matter.
• Matter exists in 3 phases:
– Solids
– Liquids
– Gases
States of Matter
Matter:
Anything that has
mass and takes up
____________.
Matter
• Atoms are the building blocks of
____________.
Matter
• Atoms are the building blocks of matter.
• Each element is made of the same kind of atom.
Matter
• Atoms are the building blocks of matter.
• Each element is made of the same kind of atom.
• A compound is made of two or more different kinds of
elements.
Elements
• Elements: any material made of only one
type of atom.
• All elements are listed on the Periodic
table of Elements.
• What are some elements that are
important to you? Explain why.
• What are some elements important to
agriculture? Explain why.
Atoms
• Atoms are the basic units of
matter.
• Atoms combine in different ways
to produce all substances.
• 100 known distinct atoms, 90 in
nature, others lab made.
Atoms
• Three structure particles: protons, neutron,
electrons.
• Protons have a positive (+) charge.
• Neutrons are neutral, no charge.
• Electrons have a negative (-) charge.
Atoms
• Protons and neutrons make up the
nucleus in the center of the atom.
• Electrons are arranged in the energy shell
orbiting the nucleus.
• A neutron is slightly smaller.
• An electron is extremely small. (1/1836th
of an amu)
Subatomic Particles
Particle
Symbol
Charge
Relative
Mass
Electron
e-
1-
0
Proton
p+
+
1
Neutron
n
0
1
LecturePLUS Timberlake
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Location of Subatomic Particles
10-13 cm
electrons
protons
nucleus
neutrons
10-8 cm
LecturePLUS Timberlake
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Student demonstration
• Human hydrogen
(H) atom model
Atomic Number
Counts the number
of
protons
in an atom
LecturePLUS Timberlake
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1. Atomic #: indicates the #
of protons.
Periodic Table
2.Name of element
3. Chemical symbol
4.Atomic Mass: is the
average mass of various
isotopes of an element.
Iron
Element
Symbol
Full element
name
Atomic Number on the Periodic
Table
Atomic Number
Symbol
11
Na
LecturePLUS Timberlake
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All atoms of an element have
the same number of protons
11 protons
Sodium
11
Na
LecturePLUS Timberlake
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Learning Check
State the number of protons for atoms of
each of the following:
A. Nitrogen
1) 5 protons
2) 7 protons 3) 14 protons
B. Sulfur
1) 32 protons
2) 16 protons
3) 6 protons
C. Barium
1) 137 protons 2) 81 protons
LecturePLUS Timberlake
3) 56 protons
20
Solution
State the number of protons for atoms of each
of the following:
A. Nitrogen
2) 7 protons
B. Sulfur
2) 16 protons
C. Barium
3) 56 protons
LecturePLUS Timberlake
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Mass Number
Counts the number
of
protons and neutrons
in an atom
LecturePLUS Timberlake
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Atomic Symbols
 Show the mass number and atomic number
 Give the symbol of the element
mass number
23 Na
atomic number
sodium-23
11
LecturePLUS Timberlake
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Number of Electrons
 An atom is neutral
 The net charge is zero
 Number of protons = Number of electrons
 Atomic number = Number of electrons
LecturePLUS Timberlake
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Subatomic Particles in Some
Atoms
16
O
31
P
65
8
15
30
8 p+
8n
8 e-
15 p+
16 n
15 eLecturePLUS Timberlake
Zn
30 p+
35 n
30 e25
Isotopes
 Atoms with the same number of protons,
but different numbers of neutrons.
 Atoms of the same element (same atomic
number) with different mass numbers
Isotopes of chlorine
35Cl
37Cl
17
17
chlorine - 35
chlorine - 37
LecturePLUS Timberlake
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Isotopes
• Isotopes are different types of atoms (nuclides) of the same
chemical element, each having a different number of
neutrons.
• In a corresponding manner, isotopes differ in mass number
(or number of nucleons) but never in atomic number.
• The number of protons (the atomic number) is the same
because that is what characterizes a chemical element. For
example, carbon-12, carbon-13 and carbon-14 are three
isotopes of the element carbon with mass numbers 12, 13
and 14, respectively.
• The atomic number of carbon is 6, so the neutron numbers
in these isotopes of carbon are therefore 12−6 = 6, 13−6 =
7, and 14–6 = 8, respectively.
Learning Check
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
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Solution
12C
13C
14C
6
6
6
#p
6
6
6
#n
6
7
8
#e
6
6
6
LecturePLUS Timberlake
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Learning Check
An atom of zinc has a mass number of 65.
A. Number of protons in the zinc atom
1) 30
2) 35
3) 65
B. Number of neutrons in the zinc atom
1) 30
2) 35
3) 65
C. What is the mass number of a zinc isotope
with 37 neutrons?
1) 37
2) LecturePLUS
65
3)
67
Timberlake
30
Solution
An atom of zinc has a mass number of 65.
A. Number of protons in the zinc atom
1) 30
B. Number of neutrons in the zinc atom
2) 35
C. What is the mass number of a zinc isotope
with 37 neutrons?
3) 67
LecturePLUS Timberlake
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Learning Check
Write the atomic symbols for atoms with
the following:
A. 8 p+, 8 n, 8 e-
___________
B. 17p+, 20n, 17e-
___________
C. 47p+, 60 n, 47 e-
___________
LecturePLUS Timberlake
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Solution
16O
A. 8 p+, 8 n, 8 e-
B. 17p+, 20n, 17e-
8
37Cl
17
107Ag
C. 47p+, 60 n, 47 e47
LecturePLUS Timberlake
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Atomic Mass on the Periodic
Table
Atomic Number
Symbol
Atomic Mass
11
Na
22.99
LecturePLUS Timberlake
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Atomic Mass
Atomic mass is the weighted average
mass of all the atomic masses of the
isotopes of that atom.
LecturePLUS Timberlake
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Example of an Average Atomic
Mass
Cl-35 is about 75.5 % and Cl-37 about
24.5% of natural chlorine.
35 x 75.5
= 26.4
100
35.5
37 x 24.5
=
9.07
100
LecturePLUS Timberlake
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Periodic Table
• Periodic table is organized by
– Periods
– Groups
•
•
•
•
•
•
across
down. Same as families
Alkali metals
Alkaline earth metals
Transition metals
Halogens
Noble gases
Metaloids
Metals
• Elements that are shiny(luster), opaque
• Good conductors of heat and electricity
• Solid at room temperature. Except
mercury.
• Have high melting points
• Malleable- can be hammered flat
• Ductile- can be pulled into wire without
breaking.
Nonmetals
•
•
•
•
•
Nonmetal have no luster
Gaseous or solid at room temperature
Low density
Poor conductor
Solid nonmetals are brittle and break easy
Metalloids
• Semimetals
• Have properties of both metals and
nonmetals.
• Some have luster, some do not.
• Melting points and density vary.
• Semiconductors: not as well as metals
Shells or orbitals
• A region of space around the atomic
nucleus within which e- reside.
– Shell 1: 2e- max
– Shell 2: 8 e- max
– Shell 3: 8 e- max
– Shell 4: 18 e- max
– Shell 5: 18 e- max
– Shell 6: 32 e- max
– Shell 7: 32 e- max
• The period the element is in on the
periodic table identifies the # of shells the
element will have.
• Valence e- : the electron in the last/ outer
most shell.
– The e- are unstable
– The e- wants to bond with other elements to
form compounds.
Fig 23.7
Ionic Bonds
Two atoms bond because of their lack of stability
of their valence e- (electron).
• The electrical force of attraction that holds ions
of opposite charge together.
• This type of bond results in a compound.
Covalent bond
23.12,23.14,23.18
• A chemical bond in which atoms are held
together by their mutual attraction for two
electrons they share.
• This type of bond results in a molecule.
• Covalent bonding is the most important type of
bonding to living organisms.
lab activity
• Bonding lab
• Atomic model lab
Chemical Reactions Are Represented
by Chemical Equations
• What is the purpose of coefficients in a
chemical equation?
• Coefficents are used to show the ratio in
which reactants combine and products for
in a chemical reaction.
How molecules are symbolized
Cl2
2Cl
2Cl2
• Molecules may also have brackets to
indicate numbers of atoms. E.g. Ca(OH)2
• Notice that the OH is a group
O Ca O
H
• The 2 refers to both H and O H
• How many of each atom are in the following?
a) NaOH
Na = 1, O = 1, H = 1
b) Ca(OH)2 Ca = 1, O = 2, H = 2
c) 3Ca(OH)2 Ca = 3, O = 6, H = 6
Balancing equations: MgO
• The law of conservation of mass states that
matter can neither be created or destroyed
• Thus, atoms are neither created or destroyed,
only rearranged in a chemical reaction
• Thus, the number of a particular atom is the
same on both sides of a chemical equation
• Example: Magnesium + Oxygen (from lab)
• Mg + O2  MgO Mg + O O  Mg O
• However, this is not balanced
• Left:
Mg = 1, O = 2
• Right: Mg = 1, O = 1
Balance equations by “inspection”
From
Mg
2Mg
Mg
Mg2
4Mg
+ O2
+ O2
+ ½O2
+ O2
+ 2 O2
 MgO
 2MgO
 MgO
 2MgO
 4MgO
is correct
is incorrect
is incorrect
is incorrect
Hints: start with elements that occur in one
compound on each side. Treat polyatomic ions
that repeat as if they were a single entity.
a) P4 + 5 O2  P4O10
b) 2 Li + 2 H2O  H2 + 2 LiOH
c) 2 Bi(NO3)3 + 3 K2S  Bi2S3 + 6 KNO3
d) C2H6 +3.5 O2  2 CO2 + 3 H2O
2 C2H6 + 7 O2  4 CO2 + 6 H2O
Balance these skeleton equations:
a)
b)
c)
d)
e)
f)
g)
h)
i)
Mg + 2HCl  MgCl2 + H2
3Ca + N2  Ca3N2
NH4NO3  N2O + 2H2O
2BiCl3 + 3H2S  Bi2S3 + 6HCl
2C4H10 + 13O2  8CO2 + 10H2O
6O2 + C6H12O6  6CO2 + 6H2O
3NO2 + H2O  2HNO3 + NO
Cr2(SO4)3+ 6NaOH  2Cr(OH)3+ 3Na2SO4
Al4C3 + 12H2O  3CH4 + 4Al(OH)3
Mixtures
• Combination of 2 or more substances in
which each substance retains its properties.
Mixture
Homogenous
mixture
Solution
Ex: air, salt and
water
Suspension
Ex: milk, blood, fog
Heterogeneous
Ex: Sand and water
Heterogeneous
• The different components can be seen as
individual substances
Homogenous
• Have the same composition throughout
mixture.
Solutions
• All components are in the same phase of
matter. ) All solid, All liquid, or All gas
• Solvent in a solution does the dissolving.
• Solute is the matter that gets dissolved.
• Example: solvent = water
solute = salt
Suspension
• Different components are in different
phases
– Example solid in a liquid
– Separation of components can be done by
using a centrifuge.