New Area of focus: Atomic Bonding New Area of focus: Atomic Bonding Copyright © 2010 Ryan P....

New Area of focus: Atomic BondingNew Area of focus: Atomic Bonding

Copyright © 2010 Ryan P. Murphy

Chemical Bonding: The attraction that Chemical Bonding: The attraction that holds atoms close to each other.holds atoms close to each other.


Ionic, Covalent, MetallicIonic, Covalent, Metallic


Ionic, Covalent, MetallicIonic, Covalent, MetallicCovalent – Share electronsCovalent – Share electrons


Ionic, Covalent, MetallicIonic, Covalent, MetallicCovalent – Share electronsCovalent – Share electronsIonic – Gain or lose electrons Ionic – Gain or lose electrons

(transfer)(transfer)


Ionic, Covalent, MetallicIonic, Covalent, MetallicCovalent – Share electronsCovalent – Share electronsIonic – Gain or lose electrons Ionic – Gain or lose electrons

(transfer)(transfer)Metallic- Many free electronsMetallic- Many free electrons


““My name is My name is Bond.Bond.””


““Covalent Covalent Bond.Bond.””


Covalent bonding occurs by a sharing Covalent bonding occurs by a sharing of valence electronsof valence electrons


Covalent bonding occurs by a sharing Covalent bonding occurs by a sharing of valence electrons of valence electrons (Strongest)(Strongest)


Covalent bonding occurs by a sharing Covalent bonding occurs by a sharing of valence electrons (Strongest) of valence electrons (Strongest) (SPONCH).(SPONCH).


Ionic bonding (+/-) Bonds created by Ionic bonding (+/-) Bonds created by the attraction of opposite charges.the attraction of opposite charges.


““Ionic Please.Ionic Please.”” ““Transferred.Transferred.”” ““Not shared.Not shared.””

Ionization: The process of removing Ionization: The process of removing electrons from an atom to form ions.electrons from an atom to form ions.


• Ionic - One atom strips electron from the other so both are now stable. Held then by + / - charge


Ionic Bonding: Forms crystal lattice.Ionic Bonding: Forms crystal lattice.


Learn more: http://web.jjay.cuny.edu/~acarpi/NSC/5-bonds.htm

http://web.jjay.cuny.edu/~acarpi/NSC/5-bonds.htm

http://web.jjay.cuny.edu/~acarpi/NSC/5-bonds.htm

Video: Ionic and Covalent Bonds

http://www.youtube.com/watch?v=Kj3o0XvhVqQ&feature=results_main&playnext=1&list=PL85B1E4851BDEE325




Metallic bonding: The bonding Metallic bonding: The bonding between atoms within metals. The between atoms within metals. The sharing of many free electrons.sharing of many free electrons.


Metallic bonding: The bonding Metallic bonding: The bonding between atoms within metals. The between atoms within metals. The sharing of many free electrons.sharing of many free electrons.


Learn more: http://www.chemguide.co.uk/atoms/bonding/metallic.html

http://www.chemguide.co.uk/atoms/bonding/metallic.html

http://www.chemguide.co.uk/atoms/bonding/metallic.html

• Activity! Generating heat by breaking metallic bonds.


• Activity! Generating heat by breaking metallic bonds. Wear Safety Goggles.


• Activity! Generating heat by breaking metallic bonds.– Bend spoon back and forth to generate very

hot temperatures, WATCH OUT!


• Activity! Generating heat by breaking metallic bonds.– Bend spoon back and forth to generate very

hot temperatures, WATCH OUT!– Do not try this in the lunchroom!


• Video! Ionic and Covalent Bonding.

• http://www.youtube.com/watch?v=QqjcCvzWwww

http://www.youtube.com/watch?v=QqjcCvzWwww


• Video Link! (Optional) Khan Academy, Atomic Bonding.– http://www.khanacademy.org/video/ionic--covale

nt--and-metallic-bonds?playlist=Chemistry

http://www.khanacademy.org/video/ionic--covalent--and-metallic-bonds?playlist=Chemistry

http://www.khanacademy.org/video/ionic--covalent--and-metallic-bonds?playlist=Chemistry

Ion: A charged atom.Ion: A charged atom. When an atom strips an electron, now one atom When an atom strips an electron, now one atom

has 1+ (cation), and the other has 1 – (anion), has 1+ (cation), and the other has 1 – (anion),



has 1+ (cation), has 1+ (cation), and the other has 1 – (anion), and the other has 1 – (anion),





““+1 Cat+1 Cationion, ,

Animal hoarding Animal hoarding addsadds

Cats. I love cats, Cats. I love cats, Cats are Cats are positive.positive.


has 1+ (cation), has 1+ (cation), and the other has 1 – (anion), and the other has 1 – (anion),





“Hoot” “Hoot” “Did anybody see me on that charged

atom.”

The closer and more tightly bound an electron is to the nucleus, the more difficult it will be to remove, and the higher its ionization energy will be.

Protons stink!

I hate being in this shell.

This is the

worst.

Nightmare

Protons stink!

I hate being in this shell.

This is the

worst.

Nightmare

This is so nice

II’’m so happy.m so happy.

The atom has a neutral charge when the number is the same.


When you remove an electron


When you remove an electron the atom becomes more positive


When you remove an electron the atom becomes more positive

Yay, we lost Yay, we lost Grumpy.Grumpy.

I feel so more I feel so more positive.positive.


When you remove an electron the atom becomes more positive (Cation +)

Yay, we lost Yay, we lost Grumpy.Grumpy.

I feel so more I feel so more positive.positive.



When you add an electron the atom becomes more negative.




Anion -




Anion -

More negativity

• Which atom below is the anion, and which is the cation?

• Sodium formed a cation because it lost 1 electron and became positive.

• Sodium formed a cation because it lost 1 electron and became positive.

Add cats, Cats are +

• Chlorine formed an anion because it gained -1 electron. More negative.

Add cats, Cats are +

• Which atom below formed a cation, and which formed an anion?

• Which Gnome is the Cation, and which Gnome is the Anion?




Cation +1 gives an electron



Cation +1 gives an electron

Anion -1 accepts an electron

• Electron Affinity: The amount of energy required to detach an electron from a singly charged negative ion.


• Will this atom want to lose this valence electron, or gain many electrons to have a full outer shell?


• Answer: This Potassium atom will want to lose this electron. It has a low electron affinity.



Who wants it?


Who wants it?

It is ionic because it's a bond between a metal(potassium) and a non-metal(chlorine). Potassium has one electron in its valence shell, and chlorine has seven electrons in its valence shell. Following the octet rule, the potassium gives an electron to the chlorine. Then the negatively charged chlorine ion and the positively charged potassium ion stick together because of their opposite charges. Ionic bonds give electrons, covalent bonds share electrons

• Will this atom want to lose these valence electrons, or gain one electron to have a full outer shell?


• Answer: This Chlorine atom will want to gain one electron rather than lose seven.


• Answer: This Chlorine atom will want to gain one electron rather than lose seven. – It has a high electron affinity.


• Answer: This Chlorine atom will want to gain one electron rather than lose seven. – It has a high electron affinity.


Learn more: Ionization. http://www.wisegeek.com/what-is-ionization.htm

http://www.wisegeek.com/what-is-ionization.htm

http://www.wisegeek.com/what-is-ionization.htm

Which atom below has a high electron affinity, and which has a low electron affinity?

Fluorine Sodium

High Electron Affinity Low Electron Affinity


Answers:

Fluorine Sodium

High Electron Affinity Low Electron Affinity


• Electronegativity increases from lower left to upper right.


• Electronegativity increases from lower left to upper right.


Moving top to bottom down the periodic table, electronegativity decreases.

H He

Li Be B C N O F Ne

Na Mg Al Si P S Cl Ar

K Ca Sc Ti Ga Ge As Se Br Kr

Electronegativ

ity

Electronegativ

ity



Note: Noble gases are missing.

• The most strongly electronegative element, Fluorine (F).




“I want electron

s.”


• The least electronegative element is Francium (Fr).





“I want to give away electrons.”





““I want to I want to gain gain electronselectrons””





““I want to I want to gain gain electronselectrons””

“You guys should get together.”

• Electronegativity is a measure of the attraction of an atom for the electrons in a chemical bond.


• Electronegativity is a measure of the attraction of an atom for the electrons in a chemical bond. – The higher the electronegativity of an atom, the

greater its attraction for bonding electrons.





“Those elements attract electrons like wicked.”




“Not the Noble Gases however.”




“Not the Noble Gases however.” “They’re wicked different.”

– Electrons with low ionization energies have a low electronegativity because their nuclei do not exert a strong attractive force on electrons.

– Elements with high ionization energies have a high electronegativity due to the strong pull exerted on electrons by the nucleus.


and Ions)Ionization energy is the energy required to remove an electron. (Gases and Ions)

• A polar bond: Results in the unequal sharing of the electrons in the bond.


• A polar bond: Results in the unequal sharing of the electrons in the bond.– When two unlike atoms are covalently bonded,

the shared electrons will be more strongly attracted to the atom of greater electronegativity


• A polar bond: Results in the unequal sharing of the electrons in the bond.– When two unlike atoms are covalently bonded,

the shared electrons will be more strongly attracted to the atom of greater electronegativity


The presence or absence of polar bonds within a molecule plays a very important part in determining chemical and physical properties of those molecules. Some of these properties are melting points, boiling points, viscosity and

solubility in solvents.

• The three classes of bonds

• The three classes of bonds– Nonpolar Covalent

• The three classes of bonds– Nonpolar Covalent– Polar Covalent

• The three classes of bonds– Nonpolar Covalent– Polar Covalent– Ionic


• The most commonly used electronegativity scale is Pauling's. Most Periodic Tables gives the value for each element.



– Differences 1.7 or greater, the bond is usually ionic, – Differences Less than 1.7, the bond is usually covalent,

» Unless the difference is less than 0.5 the bond has some degree of polarity

– Differences of less than 0.5 are considered to be nonpolar.






H2O Electron Negativity Difference







Hydrogen = 2.20Oxygen = 3.44







Hydrogen = 2.20Oxygen = 3.443.44 – 2.20 =







Hydrogen = 2.20Oxygen = 3.443.44 – 2.20 = 1.24

Try Ethane C2H6?






C2H6 Ethane Electron Negativity Diff.







Hydrogen = 2.20Carbon = 2.55







Hydrogen = 2.20Carbon = 2.55 2.55 – 2.20 =







Hydrogen = 2.20Carbon = 2.55 2.55 – 2.20 = .35

• Which one is polar covalent and which one nonpolar?

• Layering liquids with different densities.

• Use a clear container and add the following in this order….

– Corn Syrup– Water (food Coloring)– Vegetable Oil

• I would recommend completing these questions right away.

Carbon = 2.55 Hydrogen = 2.20

Carbon = 2.55 Oxygen = 3.44





Hydrogen = 2.20Carbon = 2.55 2.55 – 2.20 = .35

Oxygen = 3.44 Carbon = 2.553.44 – 2.55 = .89

Hydrogen = 2.20Oxygen = 3.443.44 – 2.20 = 1.24

Do we want to see the answers?






Hydrogen = 2.20Carbon = 2.55 2.55 – 2.20 = .35

Oxygen = 3.44 Carbon = 2.553.44 – 2.55 = .89

Hydrogen = 2.20Oxygen = 3.443.44 – 2.20 = 1.24






Hydrogen = 2.20Carbon = 2.55 2.55 – 2.20 = .35

Oxygen = 3.44 Carbon = 2.553.44 – 2.55 = .89

Hydrogen = 2.20Oxygen = 3.443.44 – 2.20 = 1.24



Differences 1.7 or greater, the bond is usually ionic, Differences Less than 1.7, the bond is usually covalent,

Unless the difference is less than 0.5 the bond has some degree of polarity

Differences of less than 0.5 are considered to be nonpolar.




Hydrogen = 2.20Carbon = 2.55 2.55 – 2.20 = .35

Oxygen = 3.44 Carbon = 2.553.44 – 2.55 = .89

Hydrogen = 2.20Oxygen = 3.443.44 – 2.20 = 1.24





• Video! Ionic and Covalent Bonding.

• http://www.youtube.com/watch?v=QqjcCvzWwww



• Video Link! Ionic and Covalent Bonds– https://www.youtube.com/watch?v=7DjsD7Hcd9U

https://www.youtube.com/watch?v=7DjsD7Hcd9U

• (Optional Link): Khan Academy

• Ionization Energy (12 min) Advanced

• http://www.khanacademy.org/video/periodic-table-trends--ionization-energy?playlist=Chemistry

http://www.khanacademy.org/video/periodic-table-trends--ionization-energy?playlist=Chemistry



• Remember:

• Covalent – Sharing an Electron many of the SPONCH elements.

• Remember:


• Ionic – Opposite charges + / -

• Remember:


• Ionic – Opposite charges + / -

• Metallic – Many electrons

• Quiz Wiz: Label as either…

• Covalent, Ionic, or Metallic 1-10


New Area of focus: Atomic Bonding New Area of focus: Atomic Bonding Copyright © 2010 Ryan P....

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Transcript of New Area of focus: Atomic Bonding New Area of focus: Atomic Bonding Copyright © 2010 Ryan P....