2nd Prelim Lecture Flashcards
This contains positively charged protons and uncharged neutrons.
nucleus
This is composed of negatively charged
electrons.
electron cloud
in the same row are similar in size and also in the same column have similar electronic
and chemical properties.
Elements
This orbital has a sphere of electron density and is lower in energy than the other orbitals of the same shell.
s orbital
An orbital has a dumbbell shape and contains a node of electron density at the nucleus. It is higher in energy than an s orbital.
p orbital
An ______ generally occurs when elements on the far left side of the periodic table combine with elements on the far right side, ignoring noble gases.
ionic bond
•A .______formed from the element on the left side attracts a negatively charged anion formed from the element on the right side. An example is sodium chloride, NaCl.
positively charged cation
This forms one covalent bond.
• When two of these atoms are joined in a bond, each has a filled valence shell of two electrons.
Hydrogen
are electron dot representations for molecules.
Lewis structures
There are three general rules for drawing Lewis structures:
- Draw only the valence electrons.
- Give every second-row element an octet of electrons, if possible.
- Give each hydrogen two electrons.
—Condensed Structures
Drawing Organic Molecules
are drawn in, but the two-electron bond lines are generally omitted and are usually drawn next to the atoms to which they are bonded.
atoms
are used around similar groups bonded to the same atom.
Parentheses
• Assume there is a carbon atom at the junction of any two lines or at the end of any line.
• Assume there are enough hydrogens around each carbon to make it tetravalent.
• Draw in all heteroatoms and hydrogens directly bonded to them.
Skeletal Structures
In, a French Chemist, classified substances as animals, vegetables or minerals on the basis of their origin. This was probably the first attempt made to distinguish substances derived from plant or animal sources from those obtained from mineral constituents.
The term organic was later applied to those compounds derived from living matter and substance originated from nonliving sources were referred to as inorganic. It is also the belief of scientist then that living organisms contained some mysterious vital force necessary to the formation of organic substance.
1685, Nicolas Lemery
cannot be prepared in the laboratory using inorganic starting materials.
Organic compounds
In, a Swedish chemist, dealt a vital force theory a serious blow when he
proved that the basic laws of chemical change applied both to organic and inorganic compounds.
1814 JJ Berzelius
The birth of modern organic chemistry was placed in. It was the year that a German professor in Chemistry, attempted to prepare ammonium cyanate (NH4CNO) by heating a mixture of two inorganic salts, potassium cyanate (KCNO) and ammonium chloride
(NH4Cl).
1828 Friedrich
Wohler,
is an organic compound found in the urine of mammals. Because of this discovery, many
other organic compounds were synthesized from inorganic starting materials in the chemical laboratories.
Urea
By this year, the vital force theory was essentially dead, and the relationship between the two
branches of chemistry was clearly recognized
1850
low melting point
2. low boiling point
3. low solubility in water; high solubility in non-polar solvents
4. flammable
5. solutions are non-conductor of electricity
6. chemical reactions are usually slow
7. exhibit isomerism
8. exhibit covalent bonding
9. exist as solids, liquids and gases at room temperature
Organic Compounds
- high melting point
- high boiling point
- high solubility in water; low solubility in non-polar solvents
- non flammable
- solutions are good conductor of electricity
- chemical reactions are rapid
- isomers are limited to a few exceptions
- exhibit ionic bonding
- exist predominantly as solids at room temperature
Inorganic Compounds
One constituent common to all organic compounds is the element.
carbon
The term organic chemistry, although no longer descriptive, implies the study of?
carbon-containing compounds
There are approximately ______ known inorganic compounds, while there are about 19 million known organic compounds
500,000
carbon has the ability to bond successively to other carbon atoms to form__________ of varying sizes.
chains and
rings
can also form equally strong bonds with a number of different elements.
Carbon
Among of these carbon can bond
hydrogen
oxygen
nitrogen
sulfur
phosphorus
halogens.
: Lasting attraction between atoms, ions, or molecules.
- Enables formation of chemical compounds.
- Related to electron arrangement in compounds.
- Types: Ionic bonds (oppositely charged ions’ attraction) and Covalent bonds (electron sharing).
- Nature of bonds closely linked to electron configurations.
- Chemical bond
- involve electron transfer between a metal (cation) and a nonmetal (anion)
- Result in electrostatic attraction between oppositely charged ions
- Transfer satisfies octet or duet rule, ensuring stability
- Formation of this driven by significant electronegativity difference
- Example: Sodium (metal) and chlorine (nonmetal) form through electron transfer
Ionic bonds
- this is denoted by a positive superscript charge (+) to the right of the atom.
- Example: Sodium atom losing one electron becomes Na+ or Na+1.
cations
is denoted by a negative superscript charge (-) to the right of the atom.
- ## Chlorine atom gaining an extra electron becomes Cl–.
anion
These ions form for stability according to the octet rule.
Anion and Cation
- Involve sharing of valence electrons between two nonmetal atoms.
- Sharing achieves octet rule, enhancing stability.
- Example: Carbon shares electrons with chlorine to form CCl4 (carbon tetrachloride).
- can be single, double, or triple, each representing different electron sharing:
Covalent bonds
occur when four electrons are shared between the two atoms and consist of one sigma bond and one pi bond.
Double bonds
involve sharing of two electrons, forming one sigma bond between atoms.
Single bonds
occur when six electrons are shared between the two atoms and consist of one sigma bond and two pi bonds.
Triple bonds
represents a group or entire series of related compounds.
can be used to identify the number of hydrogen atoms.
a) Alkanes - CnH2n + 2 Note: letter n represents the number of C atoms
Type or general formula
- has three carbon atoms CnH2n + 2
C3H2(3)+2 = C3H8
Propane
has five carbon atoms
CnH2n + 2 C5H2(5)+2 = C5H12
Pentane
CnH2n
Alkenes
CnH2n
C3H2(3) = C3H6
Propene
CnH2n
C5H2(5) = C5H10
Pentene
– shows the actual number of atoms of the elements in the molecule.
Molecular formula
shows the arrangement of atoms or group of atoms in the molecule.
Condensed or semi-structural formula
portrays all the bonds of the atoms in the molecule.
Structural formula
- (skeletal formula) represent organic compounds with carbon atoms at the corners and ends of lines.
- Each line signifies a carbon-carbon bond.
- Each carbon atom is implied to be bonded to enough hydrogen atoms to fulfill the tetravalency requirement.
Line-angle formulas
• have identical molecular formulas but different spatial arrangements of atoms.
• may not have similar chemical or physical properties.
Isomers
refers to the existence or possibility of isomers.
Isomerism
- have identical molecular formulas but different arrangements of carbon skeletons.
Chain isomers
Can be arranged as one continuous chain or with multiple side groups branching off.
Carbon chains
the basic carbon ‘skeleton’ remains unchanged but the important groups are moved around on that skeleton.
Position isomers
contain the same molecular formula but the atoms are rearranged to give a different functional group.
Functional isomers
- ## differ in spatial arrangement of atoms, not in atomic connectivity.
Stereoisomers
are a notable type of Stereoisomers
Mirror-image stereoisomers
– (Ci-trans) are compounds that differ only in a way that their atoms are arranged in space.
Geometric isomers
– differ by the placement of different substituents around one or more atoms in a molecule.
come in pairs, and they can usually contain a chiral center (this is a carbon atom with four different atoms or group of attached to it).
Optical isomers
are organic compounds mainly containing hydrogen and carbon atoms.
They are naturally-occurring compounds and form the basis of crude oil, natural gas, coal, and other important energy sources.
Hydrocarbons
Hydrocarbons themselves are separated into two types, the
aliphatic hydrocarbons
cyclic hydrocarbons.
are compound whose carbon chains are connected by means of single, double or triple bonds to form non-cyclic structure,
Aliphatic hydrocarbons
are compounds in cyclic or close chain series.
cyclic hydrocarbons
– carbon chains are connected by means of single bonds all throughout the structure. Example: alkanes
Saturated hydrocarbons
– carbon chains are connected by means of either double or triple bonds. Examples: alkenes and alkynes
Unsaturated hydrocarbons
- organic compounds that contain one or more closed rings of carbon atoms which maybe saturated or unsaturated, but do not have aromatic characteristics.
Alicyclic hydrocarbons
(or arenes) - are cyclic hydrocarbons that contain at least one 6-carbon membered ring with alternate double and single bonds in the structure.
Aromatic hydrocarbons
- are cyclic hydrocarbons that contain other elements aside from carbon in the structure.
Heterocyclic hydrocarbons
This is the simplest type of hydrocarbon , which contain carbon to carbon single bonds. They have the general formula of C.Hen +2 in which the letter ‘n’ represents the number of carbon atoms in the molecule.
alkanes
It is the recognized world authority in developing standards for the naming of the chemical elements and compounds.
International Union of Pure and Applied Chemistry (IUPAC)
Steps in naming alkanes without branched carbon chain:
1.Count the number of carbon atoms.
2. Use the prefixes corresponding to the number of carbon atoms.
3. To the prefix, attach the ending -ane for alkanes.
4. For IUPAC name, just remove the letter n in common names
’’ means normal which indicates that the carbon chain is in normal form or in straight chain. It will be used only if there are three or more carbon chains.
n
Steps in naming alkanes with branched carbon chain using the Common names.
- Count the number of carbon atoms.
- Use the prefixes corresponding to the number of carbon atoms.
- Use the prefix iso- if there is one substituent connected in the carbon chain, and neo- if there are two substituents connected.
used as substituents -
This formed by removing one hydrogen from the alkane chain. The removal of this hydrogen results in a stem change from -ane to -yl to indicate in this group
The removal of a hydrogen from methane, CH, creates a methyl group -CH3,
alkyl groups
is the common name since there is only one substituent in the structure comprising of five carbon atoms, and in this system of naming, we will count all the carbons present in the structure, while in IUPAC system, we give separate name for the parent chain and the substituents (or the branch).
Iso-pentane
- Organic coupling reaction using sodium metal and two alkyl halides to produce a higher alkane.
- Dry ether chosen as solvent to prevent reaction with sodium.
- Dry ether is non-polar and aprotic, making it ideal for this
Wurtz Reaction:
-: Addition of water to _________ to produce an alkane.
- formation involves using magnesium ribbon.
- Magnesium oxide coating on magnesium ribbon prevents reactions with organic halides.
Hydrolysis of Grignard Reagent
– is the addition of hydrogen molecules to alkenes in the presence of catalyst such as Platinum (Pt), Nickel (Ni), or Palladium (Pd). This is what we called addition reaction.
is important in food industry such as in preparation of shortening or margarine. It makes the liquid oil to become more solid or spreadable.
The use of ________ process help extend the shelf life of the food and maintain flavor stability.
Hydrogenation of Alkenes
