Creepy Covalent Bonds (please read the blog. I put a lot of work into it.)

HAPPY HALLOWEEN, EVERYONE... which calls for a special blog. hehehe

{in class: we went over the quiz and took notes. ON Tues.- Outline due and Ch. 5 test. ON Wed.- Ch. 6 quiz. START MEMORIZING THE TABLES 1,2,and 5 ON PGS. 221, 226, AND 230. Dr. B said, "if you want your grades to improve, start now!" Quizes will be taken by tables}

Formation of a Covalent Bond

• Most atoms (and zombies) have a lower Potential Energy when they are bonded with other atoms (or zombies) than when the atom/zombie is alone.
• The chart in our book on pg. 179 shows the P.E. changes during formation of H-H bond

(SHE ALWAYS ASKS QUESTIONS ABOUT THIS CHART!!!)

• Suppose you have two atoms: the electron of one atom ATTRACTS the proton of the other atom (like kids and candy)
• in these same atoms, the electrons in the different atoms REPEL each other (same with the protons) (like candy and evil dentists)

--> These forces cancel out to form a covalent bond where the P.E. is lowest (they are chained together for eternity!!!!!! or until something breaks them up...)

Characteristics of a Covalent Bond

(VOCAB ALERT!)

• bond length- the distance between two bonded atoms at the minimum P.E.

--> The average distance between two bonded atoms

• Atoms release energy forming covalent bonds (like a mummy released from the grave!)
• The same amount of energy must be added to separate the atoms (stuff that mummy back in the grave! haha Take that mummies!)

(VOCAB ALERT!)

• bond energy- the energy required to break a chemical bond and form isolated atoms

• Shared electrons of two atoms in a covalent bond form overlapping orbitals

--> atoms are jealous of noble gases, so they want to make their outer shells like a noble gas's (then they can overthrow the noble gases and rule the periodic table muahaha!)

ex.- two bonded H atoms (with the overlapping orbitals) can each have He's electron configuration

The Octet Rule

• the reason noble gases are unreactive is because their electron configuration is esp. stable

--> stability comes from full s and p orbitals

• Covalent bonding allows other atoms to reach this stability

(IMPORTANTE!!!)

• OCTET RULE- Chemical compounds tend to form sa that each atom, by gaining, losing, or sharing electrons, has an octet in its highest energy level

[THIS RULE APPLIES ONLY TO THE MAIN GROUP ELEMENTS IN THE 2ND PERIOD AND BELOW]

(ALSO IMPORTANTE!!!)

• There are exceptions to the octet rule!- any atoms that can't fit 8 electrons or can fit more than 8 electrons in its outermost energy shell
• the exceptions are- ARGGGGGGGGGGGGHHHHHHHHHHHHHHHHH! (the writer of this blog was dragged away by disgruntled zombies, an evil dentist, mummies, and jealous elements)

(we will cover what the exceptions are on Monday)