Organic Chemistry Flashcards
How many valence electrons does carbon have?
4
What is carbons electron configuration? And its valence shell configuration?
1s2, 2s2, 2p2
Valence shell = 2s2, 2p2
What is carbons electronegativity number?
2.5
Which element has the highest electronegativity and what is it?
Fluorine
4
What bond type does carbon have? What are the pros of this?
4 Covalent (between atoms with equal negativity) And 4 polar covalent (atoms with differing electronegativity) Means carbon can bond to other atoms in a lot of different combinations and form many different types of structures
What is the empirical formula?
The simplest while number ratio of elements
What is the molecular formula?
The actual number of atoms of each element
What is the structural formula?
Minimal detail for an unambiguous structure
Writes out every compound in molecule
What is the displayed formula
Relative placing of atoms and bonds between them (diagram)
What is the skeletal formula
The carbon skeleton and functional groups only (very basic diagram)
Describe sigma bonds
When 2 orbitals overlap as 2 atoms approach
End to end overlap bond formed = sigma
Electrons of one atom attracted to nucleus of the other
Attraction continues until repulsion between the 2 nuclei outweighs it
What’s is hybridisation?
Combining 2+ atomic orbitals from the same atom to create new orbitals
Describe sp3 hybridisation
S and p orbitals are mixed to form hybrid orbitals
1 s and 3 p orbitals are mixed (a 2s electron prompted into empty 2p orbital = 4 unpaired electrons)
Describe sp2 hybridisation
One s orbital and two p orbitals hybridise and form sigma bonds (one p orbital left over)
Sp2 hybridisation gives a bond angle of 121.3 degrees
The 2 pure p orbitals of the 2 carbon atoms can overlap sideways to form a pi bond
What is a pi bond
covalent chemical bonds where two lobes of an orbital on one atom overlap two lobes of an orbital on another atom and this overlap occurs laterally
Describe benzene structure
- planar molecule
- each carbon is sp2 hybridised
- 6 electrons in pure p orbitals capable of overlapping
- get delocalisation over the ring
Describe sp hybridisation
- 2 pure p orbitals left over per carbon atom = 2 pi bonds
- 1s atom and 1p atom hybridise
- each carbon atom forms 2 sigma bonds and 2 pi bonds
What are the properties of organic compounds? (4)
- physical and chemical behaviour heavily influenced by molecules polarity
- most are not soluble with water
- somewhat soluble if have oxygen or nitrogen atoms: electronegative atoms form hydrogen bonds with the water
- many undergo combustion and burn vigorously in air
Describe polarity of organic molecules
- covalent bond between 2 carbons non polar because electrons shared equally
- most elements found in organic compounds more electronegative than carbon (except H)
- polarity of molecule determined by polarity of bonds and structure
- bond can be polar but molecule non polar if has symmetrical arrangement of polar bonds that cancels out the dipoles.
What are the 2 classes of organic compounds
-aromatic
Contains cyclic conjugated (alternating double and single bonds) double bond system with 4n + 2pi electrons
-aliphatic
All other compounds without a ring system
Why do we have classes of organic compounds
- there are millions of different types
- characteristic structural features ‘functional groups’
- allows to classify and name compounds within families
- identification of functional groups helps to predict reactivity of a compound
Oxidation of carbon
They form additional bonds to oxygen
Reduction of carbon
They form additional bonds to hydrogen
Substitution
Exchange of one atom in a molecule with another atom/group of atoms
Elimination
Single reactant split into 2 products
Addition
2 reactants add together to form single product
Homolytic reaction of carbon compound
- 1 electron transferred to each atom
- formation of radicals
Heterolytic reaction of carbon compound
- 2 electrons transferred to another atom
- formation of ions
What is a radical?
Atom containing at least 1 unpaired electron
