Chemblog!

AP: we talked about how molecular orbitals can form from atomic orbitals as atoms bond to form a molecule. This theory is an alternative model for looking at how electrons are distributed throughout a molecule and what specific energies those electrons have. So, it is the same as the quantum mechanical model of an atom as applied to the molecule. The theory predicts bond order, molecular polarity, paramagnetism (in O2, which shows the success of the model), and other physical and chemical properties. However, getting pictures and solving for the energies of electrons in particular molecular orbitals requires sophisticated math and supercomputers. So, we just intro the topic by applying the theory to diatomic molecules.
We also showed that, for OXOACIDS, each "H" in the formula IS NOT BONDED TO THE CENTRAL ATOM but rather to one of the Oxygen terminal atoms, which is why they are called oxoacids. So, in nitric acid, the H is bonded to one of the terminal oxygens that is bonded to the N. Don't forget that.

Regents: we had another brief quiz (to be graded soon, check website tomorrow). We reviewed metallic vs. ionic bonding and the physical properties associated with each: metals= good electrical conductors, malleable, high melting points; salts = poor electrical conductors (IN SOLID PHASE ONLY), brittle, and high melting points.
We then began our next MAJOR part of the course that requires practice and repetition to master: NAMING COMPOUNDS.
We talked about the rules for naming binary salts of representative and transition metals as well as salts of polyatomic ions (ternary salts). We finished with "hydrates". On Monday, we will learn how to name molecules and acids.

Honors: we went over the rest of the exceptions to the octet rule: Be and B molecular compounds. Remember, they CAN acquire an octet BUT you can draw legitimate Lewis structures of these Be and B molecular compounds with a quartet and a sextet of electrons, respectively. We also showed that, for compounds of elements in PERIODS 3 through 7, an "expanded octet" is possible and you WON'T have to guess when! Just follow the Lewis structure rules for single bonding to ALL terminal atoms and you will win.
We then began our next MAJOR part of the course that requires practice and repetition to master: NAMING COMPOUNDS.
We talked about the rules for naming binary salts of representative and transition metals as well as salts of polyatomic ions (ternary salts). On Monday, we will learn how to name hydrates, bases, molecules and acids. I will give you HUNDREDS of practice examples for hw until you know how to name any simple salt, base, molecule, acid and hydrate. Our test is next Tuesday and it will cover everything from the beginning of the Bonding Unit notes.
Monday, I will discuss the repeated failure to answer questions that were asked on your last test as well as the ignorance in following directions and the obvious lack of study (my definition of studying) and effort from MANY of you. Sadly, I can't force you to follow my directions and advice. If I could, everyone would be doing well. I can only clearly and explicitly show you and tell you what to do (see notes, worksheets, and complete explanations posted on the website as well as the mantras that I repeat in class) and hope that you follow the direction. Those who, for the sixth test in a row now, have ignored my advice and direction, once again wrote false, irrelevant, and/or incomplete answers or WASTED at least 10 to 15 minutes writing information that wasn't even asked for.