# Atomic Structure and the Periodic Table

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Atomic Structure and the Periodic Table
Students can describe the parts of an atom Students can read the element information on the periodic table Students can describe the reactivity of alkali metals Students can describe how various types of bonding in different categories of materials effects their behavior

Atoms smallest particle of an element that has the properties of the element made of 3 basic subatomic particles there are now many more subatomic particles – theoretical physics

Subatomic Particles Name Protons (p or +) Neutrons (n) Electrons (e-)
Charge Location Mass “Job” Number

Subatomic Particles Charge +1 No charge -1 Protons (p or +)
Name Protons (p or +) Neutrons (n) Electrons (e-) Charge +1 No charge -1 Location Mass “Job” Number

Subatomic Particles Location in nucleus in shells around nucleus
Name Protons (p or +) Neutrons (n) Electrons (e-) Charge +1 No charge -1 Location in nucleus in shells around nucleus Mass “Job” Number

nucleus small, dense center of atom
contains almost all the mass of the atom contains protons and neutrons

in shells around nucleus
Subatomic Particles Name Protons (p or +) Neutrons (n) Electrons (e-) Charge +1 No charge -1 Location in nucleus in shells around nucleus Mass ≈ 1 amu ≈ 2000x smaller “Job” Number

Atomic Mass Unit (amu) metric unit to measure the mass of VERY small objects (particles) a unit to measure the mass of atoms Just like we have light years for measuring very large distances

in shells around nucleus
Subatomic Particles Name Protons (p or +) Neutrons (n) Electrons (e-) Charge +1 No charge -1 Location in nucleus in shells around nucleus Mass ≈ 1 amu ≈ 2000 x smaller “Job” Determines identity of element Supplies proper mass to hold nucleus together bonding/ how it reacts Number

Subatomic Particles Number Atomic # Atomic mass – atomic # =
Name Protons (p or +) Neutrons (n) Electrons (e-) Charge +1 No charge -1 Location in nucleus in shells around nucleus Mass ≈ 1 amu ≈ 2000 x smaller “Job” Determines identity of element Supplies proper mass to hold nucleus together Determines bonding/ how it reacts Number Atomic # Atomic mass – atomic # = # of neutrons Same as # of protons

# of protons atomic number whole number on periodic table
number of protons in an atom of an element does NOT vary in an element – the same in all atoms of an element Use the flexcam and a copy of the periodic tables they have in their notebooks to show them the location of the atomic number and atomic mass. Try several examples.

# of electrons atoms are neutral (+) = (-)
# of protons = # of electrons p = e- Do several examples.

atomic mass (weight) decimal number on the periodic table – it is for all the atoms of the element number of protons plus the number of neutrons – it’s an average on the table weighted average of all the isotopes of that element the mass of one atom is a whole number use the average weight of students analogy (all girls = 100 lbs, all boys = 200 lbs. – same # of girls and boys – more girls than boys)

Isotopes iso = same atoms of the same element with different numbers of neutrons have different atomic masses but the same atomic number some are stable, some are radioactive (carbon-12 and carbon-14)

# of neutrons atomic mass n + p - atomic # - p # of neutrons n
Work some sample problems on how to determine the # of protons, electrons, and neutrons in an atom of an element. Let the students choose the elements.

Free Write What do you know about: atoms the periodic table

Periodic Table rows How is the periodic table arranged?
arranged by increasing atomic number rows called periods tells number of electron shells number them down the left side of the periodic table – 1 through 7 discuss the history of the periodic table briefly. Use the overhead to show them how to mark/label the rows.

Periodic table lesson plans

Periodic Table columns called families or groups
elements in same column have similar chemical properties same number of valence electrons

Periodic Table valence electrons electrons in outermost shell
involved in bonding number the columns on your periodic table with the correct number of valence electrons Use the overhead to show them how to mark/label the columns.

Stability stable number of electrons = 8 in the outermost shell
8 valence e- octet rule exception – 1st shell is stable with 2 e-

Metals 1 to 3 valence electrons givers of electrons lose electrons
make (+) ions left side of periodic table

Nonmetals 5 to 8 valence electrons takers of electrons gain electrons
make (-) ions right side of periodic table

Ion atom with a charge atom has gained or lost electrons
gained e- = (-) charge lost e- = (+) charge (+) ion = cation (-) ion = anion

Column 8 Noble gases very stable don’t want to form compounds or bonds

Column 7 halogens want one more electron most reactive nonmetals
can take an electron from almost anyone

Column 1 alkali metals want to give away one electron
most reactive metals

Alkali metals on the show brainiac

Bonding atoms achieve a stable number of electrons (ionic and covalent) involves valence (outer) electrons make compounds and/or solids fill out types of bonding chart using overhead show overhead of metallic bonding draw examples of ionic bonding – use skeletal models - MgO, NaCl, CaCl2, K2S draw examples of covalent bonding – use skeletal models – CO2, H2O, O2

intermolecular forces
Type of bonding metallic ionic covalent intermolecular forces Type of elements used Givers &/or takers of electrons Description Type of material formed Strength of bond Properties Produced

intermolecular forces
Type of bonding metallic ionic covalent intermolecular forces Type of elements used Between metals Metals and nonmetals Between nonmetals Between molecules Givers &/or takers of electrons Description Type of material formed Strength of bond Properties Produced

intermolecular forces Between givers and takers
Type of bonding metallic ionic covalent intermolecular forces Type of elements used Between metals Metals and nonmetals Between nonmetals Between molecules Givers &/or takers of electrons Between givers Between givers and takers Between takers Description Type of material formed Strength of bond Properties Produced

(-) ions that are attracted to each other. Share e-
Type of bonding metallic ionic covalent intermolecular forces Type of elements used Between metals Metals and nonmetals Between nonmetals Between molecules Givers &/or takers of electrons Between givers Between givers and takers Between takers Description Valence e- roam freely between many atoms (delocalized). Sea of e- surrounding (+) kernels. Transfer e- Makes (+) and (-) ions that are attracted to each other. Share e- Forms discrete molecules. Hold covalently bonded molecules together as a solid. Type of material formed Strength of bond Properties Produced

Type of material formed Solid metallic elements and alloys
Type of bonding metallic ionic covalent intermolecular forces Type of elements used Between metals Metals and nonmetals Between nonmetals Between molecules Givers &/or takers of electrons Between givers Between givers and takers Between takers Description Valence e- roam freely between many atoms (delocalized). Sea of e- surrounding (+) kernels. Transfer e- Makes (+) and (-) ions that are attracted to each other. Share e- Forms discrete molecules. Hold covalently bonded molecules together as a solid. Type of material formed Solid metallic elements and alloys Ceramics and glass Polymers and some ceramics/ glasses Helps form solid polymers Strength of bond Properties Produced

intermolecular forces
Type of bonding metallic ionic covalent intermolecular forces Type of elements used Between metals Metals and nonmetals Between nonmetals Between molecules Givers &/or takers of electrons Between givers Between givers and takers Between takers Description Valence e- roam freely between many atoms (delocalized). Sea of e- surrounding (+) kernels. Transfer e- Makes (+) and (-) ions that are attracted to each other. Share e- Forms discrete molecules. Hold covalently bonded molecules together as a solid. Type of material formed Solid metallic elements and alloys Ceramics and glass Polymers and some ceramics/glasses Helps form solid polymers Strength of bond Relatively strong Very strong Weak Properties Produced

intermolecular forces high melt temps, nonconductors as solids,
Type of bonding metallic ionic covalent intermolecular forces Type of elements used Between metals Metals and nonmetals Between nonmetals Between molecules Givers &/or takers of electrons Between givers Between givers and takers Between takers Description Valence e- roam freely between many atoms (delocalized). Sea of e- surrounding (+) kernels. Transfer e- Makes (+) and (-) ions that are attracted to each other. Share e- Forms discrete molecules. Hold covalently bonded molecules together as a solid. Type of material formed Solid metallic elements and alloys Ceramics and glass Polymers and some ceramics/glasses Helps form solid polymers Strength of bond Relatively strong Very strong Weak Properties Produced Good conductors, workable, corrode easily, generally high melt temps but variable Brittle, high melt temps, nonconductors as solids, don’t corrode Insulators, Help determine a lot of properties of covalent compounds (polymers). Soft and plastic

Metallic Bonding All pure metals have metallic bonding and therefore exist as metallic structures.  Metallic bonding consists of a regular arrangement of positive ion cores of the metals surrounded by a mobile delocalized sea of electrons.

Metallic Bonding Each atom donates its valence electrons to the whole
Atom therefore becomes a cation (here called an ion core) Donated electrons form an electron cloud surrounding all the ion cores Electron cloud binds all the ion cores together by coulombic forces

Metallic Bonding Valence electrons are delocalized:
Shared by all atoms in the material Electrons are free to drift throughout the material Provides unique properties only found in metals shiny metallic luster good electrical and thermal conductivity many others ...

Metallic Bonds: Mellow dogs with plenty of bones to go around
These bonds are best imagined as a room full of puppies who have plenty of bones to go around and are not possessive of any one particular bone.  This allows the electrons to move through the substance with little restriction.  The model is often described as the "kernels of atoms in a sea of electrons."

http://www. matsceng. ohio-state

low to moderate; ductile, malleable soft and plastic
Ionic Covalent Metallic Intermolecular Bond strength strong very strong moderate and variable weak Hardness moderate to high very hard, brittle low to moderate; ductile, malleable soft and plastic Electrical conductivity conducts by ion transport only when dissociated insulator in solid and liquid good conductors; by electron transport insulators in solid and liquid states Melting point low generally high Solubility soluble in polar solvents very low solubilities insoluble soluble in organic solvents Examples most minerals diamond, oxygen, organic molecules Cu, Ag, Au, other metals ice, organic solids (crystals)

Ionic Bonding (ceramics and polymers)

Ionic Bonds: One big greedy thief dog!
Ionic bonding can be best imagined as one big greedy dog stealing the other dog's bone.  If the bone represents the electron that is up for grabs, then when the big dog gains an electron he becomes negatively charged and the little dog who lost the electron becomes positively charged.  The two ions (that's where the name ionic comes from) are attracted very strongly to each other as a result of the opposite charges.

Sodium lets Chlorine use its valance electron

http://www. matsceng. ohio-state

http://www. matsceng. ohio-state

Covalent Bonding (Ceramics)

Covalent Bonds: Dogs of equal strength.
Covalent bonds can be thought of as two or more dogs with equal attraction to the bones.  Since the dogs (atoms) are identical, then the dogs share the pairs of available bones evenly.  Since one dog does not have more of the bone than the other dog, the charge is evenly distributed among both dogs.  The molecule is not "polar" meaning one side does not have more charge than the other.

Polar Covalent Bonds: Unevenly matched but willing to share.
These bonds can be thought of as two or more dogs that have different desire for bones.  The bigger dog has more strength to possess a larger portion of the bones.  Sharing still takes place but is an uneven sharing.  In the case of the atoms, the electrons spend more time on the end of the molecule near the atom with the greater electronegativity (desire for the electron) making it seem more negative and the other end of the molecule seem more positive.

http://www. matsceng. ohio-state

Covalent Network Solid
only covalent bonds extremely large molecules or networks usually have at least one element from carbon family very strong and hard very high melt T° some glass and ceramics, diamond polymers are usually not because they make linear chains instead of networks

Read the 4 slides and take the quiz at the end Patterns in the periodic table Ionic bonding Electron numbers ions and aions Covalent bonding Structure of the atom