CHEM1011 Lecture Notes - Lecture 30: Catenation, Atomic Number, Antibiotics
9 Jun 2018
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Lecture 30: Introduction to organic chemistry
What is organic chemistry?
- Cheistry of life proteis, sugars, ulei aids…
Protection, improvement, creation
- Based around the chemistry of carbon
A few other elements (mainly H)
- Concerns
Transformations (reactivity)
Creation (synthesis) of organic structures
Organic medicines
- Antibiotics
- Anticancer agents
- HIV/AIDS Drugs
All built on scaffolds of carbon
Carbon makes awesome scaffolds
Carbon has unique properties
- Atomic number 6
1s22s22p2
Valence of 4
** Forms 4 bonds to completely fill outer shell **
Carbon has unique properties
- C can bond to itself, to metals, to heteroatoms
- C-C and C-H bonds are strong, non-polar and unreactive
Make great scaffolds
- Geometrically flexible
Capable of catenation (linkage of atoms of the same element into longer chains)
Forms chains, rings, multiple bonds
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2
Bonding and VSEPR
Covalent bonds
- Form between atoms with a small difference in tendency to lose or gain electrons
- Require electron sharing between atoms
- Formed between non-metals, which combine together by sharing electrons
Lewis structures
- Draw valence electrons as dots
- Stable molecule has noble gas configuration (8 electrons or 2 for H)
- In covalent bonds, each atom counts he shared electrons as belonging entirely to itself
The number of covalent bonds formed depends on how many electrons are required to complete
an octet.
C requires 4 electrons to complete octet, so forms 4 covalent bonds e.g. methane (CH4)
VSEPR
Valence Shell Electron Pair Repulsion Theory (VSEPR)
- Each group of valence electrons around a central atom is located as far as possible from
the others to minimise repulsions
- A group of electrons can be a lone pair, a single bond, a double bond, a triple bond etc.
- The arrangement of groups around a central atom gives a molecule shape
What does this picture mean?
- Properties depend on structure
- Huge number of organic compounds (and more to be discovered)
- To communicate unambiguously, need to master Representation and Nomenclature
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Che(cid:373)istry of life (cid:894)protei(cid:374)s, sugars, (cid:374)u(cid:272)lei(cid:272) a(cid:272)ids (cid:895) ** forms 4 bonds to completely fill outer shell ** C can bond to itself, to metals, to heteroatoms. C-c and c-h bonds are strong, non-polar and unreactive. Capable of catenation (linkage of atoms of the same element into longer chains) Form between atoms with a small difference in tendency to lose or gain electrons. Formed between non-metals, which combine together by sharing electrons. Stable molecule has noble gas configuration (8 electrons or 2 for h) In covalent bonds, each atom counts he shared electrons as belonging entirely to itself. The number of covalent bonds formed depends on how many electrons are required to complete an octet. C requires 4 electrons to complete octet, so forms 4 covalent bonds e. g. methane (ch4) Each group of valence electrons around a central atom is located as far as possible from the others to minimise repulsions.
