Organic Chem Ch. 1.pdf

4 Pages
Unlock Document

University of Massachusetts Amherst
CHEM 261
Paul Lahti

Chapter 1 Structure and Bonding Organic chemistry deals with living things and the fact that their remains contain many organic compounds Proteins Make up hair DNA Controls genetic makeup FatsLipids Crucial compounds in living cells All life on Earth is completely dependent upon organic chemistry Organic chemistry is the study of primarily carbonbased compounds 90 of more than 30 million compounds contain carbon All about where are the electrons andor to where are the electrons moving Friedrich Wohler is believed to be the first organic chemist Karl Goessman was one of his students and he also was a key player in the development of the UMass chemistry department Atom Consists of a dense positively charged nucleus surrounded at a relatively large distance by negatively charged electronsThe nucleus consists of subatomic particles called protons which are positively charged and neutrons which are electrically neutralBecause an atom is neutral overall the number of positive protons in the nucleus and the number of negative electrons surrounding the nucleus are the same Isotopes Atoms with the same atomic number but different mass numbers The weighted average mass in atomic mass units amu of an elements naturally occurring isotopes is called the elements atomic mass 12 Atomic Structure Orbitals Orbital Describes the volume of space around a nucleus that an electron is most likely to occupy Also referred to as a wave function Most concerned with s and p orbitals which are most common in organic and biological chemistry Sorbital is spherical with a nucleus at its center Porbital is dumbbell shaped Dorbitals are cloverleafshaped The fifth Dorbital is shaped like an elongated dumbbell with a doughnut around the middle Electron Shell Centered around the nucleus and having successively larger size and energy Different shells contain different numbers and kinds of orbitals and each orbital within a shell can be occupied by two electrons Node Area between two orbitals where there is zero electron density 13 Atomic Structure Electron Configurations GroundState electron Configuration The lowest energy arrangement of an atom which includes a listing of the orbitals occupied by its electrons 3 Rules must be followed to achieve this Rule 1 The lowest energy orbital fills up first according to the order 1s2s2p3s3p4s3d which is also known as the aufbau principle Rule 2 Electrons act in some ways as if they were spinning around an axis somewhat as the earth spins This spin can have two orientations denoted as up and down Only two electrons can occupy an orbital and they must be of opposite spin a statement called the Pauli exclusion principle Rule 3 Is two or more empy orbitals of equal energy are available one electron occupies each with spins parallel until all orbitals are halffull a statement called Hunds rule 14 Development of Chemical Bonding Theory
More Less

Related notes for CHEM 261

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.