1. Structure and Bonding, Slides of Organic Chemistry

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Atorvastatin

Serotonin Caffeine

Cholesterol

Paracetamol

- Toben Bergman (1770) - First to make distinction between organic and inorganic chemistry - “organic” substances → derived from living organisms - “inorganic” substances → found in minerals

• Organic compounds were low-melting, difficult to isolate and purify vs high-melting inorganic compounds

Origins of Organic Chemistry

- VITAL FORCE THEORY (mid-1700s) - “Vital Force” - assumed reason for the differences between the behavior of organic and inorganic compounds - Result of organic compounds’ origin in living sources - Due to the Vital Force Theory, scientists believed organic compounds could not be prepared and manipulated in the laboratory.

Origins of Organic Chemistry

- Friedrich Wohler (1828) - Converted the “inorganic” salt ammonium cyanate into the “organic” substance urea, which has been derived from human urine - Proved that organic compounds can be synthesized in the laboratory using inorganic compounds

Origins of Organic Chemistry

ORGANIC CHEMISTRY

• The study of carbon compounds

WHY CARBON?

• 4A element
• Can share 4 valence electrons and form four strong covalent bonds
• Carbon atoms can bond with other carbon atoms, forming chains and rings
• Can form diverse, complex compounds

What is Organic Chemistry?

Atomic Structure

- Nucleus - Very dense (10-14^ to 10-15^ m in diameter), positively-charged center composed of protons and neutrons - Electrons - Surrounds the nucleus at a relatively large distance (10-10)

• Typical diameter of an atom is about 2 x 10 -10^ m or 200 picometers (1 pm = 10 -12^ m)

1-1 Atomic Structure: The Nucleus

Atomic Number (Z)

• Number of protons (or electrons) an atom contains
• The same for all atoms of a given element (e.g. 6 for carbon) Mass Number (A)
• Total number of protons and neutrons in an atom’s nucleus
• Can differ between isotopes of an element - Isotopes → same atomic number, different mass number Atomic Mass
• weighted-average mass in atomic mass units (amu) of an element’s naturally-occurring isotopes

1-1 Atomic Structure: The Nucleus

QUANTUM MECHANICAL MODEL OF THE

ATOM

1-2 Atomic Structure: Orbitals

ATOMIC ORBITALS

• Four different kinds of orbitals: s, p, d, and **_f
• s orbital_** - spherical - p orbital - dumbbell-shaped - d orbital - four are clover-leaf shaped, the fifth is an elongated dumbbell with a doughnut around its middle
• Organic chemistry is primarily concerned with the s and p orbitals

1-2 Atomic Structure: Orbitals

ELECTRON SHELLS

• The orbitals in an atom are organized into different electron shells , centered around the nucleus, and successively increasing in size and energy
• Contain different numbers and kinds of orbitals
• Each orbital can be occupied by two electrons - 1 st^ shell - 2 nd^ shell - 3 rd^ shell - contains one 1s orbital (2 total e-^ ) - contains one 2s orbital and three 2p orbitals (8 total e-^ ) - contains one 3s orbital, three 3p orbitals, and five 3d orbitals (18 total e-^ )

1-2 Atomic Structure: Orbitals

ELECTRON SHELLS

1-2 Atomic Structure: Orbitals

WRITING GROUND-STATE ELECTRON CONFIGURATION

Rule 1: Aufbau Principle. The lowest-energy orbitals fill up first, according to the order described by the 1s → 2s → 2p → 3s → 3p → 4s →3d

Rule 2: Pauli Exclusion Principle. Only two electrons can occupy an orbital, and they must be of opposite spin

Rule 3: Hund’s Rule. For orbitals of equal energy, one electron occupies each with spins parallel until all orbitals are half-full

1-3 Atomic Structure: Electron Configurations

WRITING GROUND-STATE ELECTRON CONFIGURATION

1-3 Atomic Structure: Electron Configurations