CHEM 120 Week 8 Final Exam Review (2022)1. Question: Know what is the atomic number, atomic mass, protons, neutrons & electrons
Atomic number – is the number of protons in the nucleus of an atom of any element
Atomic mass – is expressed in amu; is the wighted average Protons – are positiv...
CHEM 120 Week 8 Final Exam Review
1. Question: Know what is the atomic number, atomic mass, protons, neutrons
& electrons
Atomic number – is the number of protons in the nucleus of an atom of any
element
Atomic mass – is expressed in amu; is the wighted
average Protons – are positively charged particles in the
nucleus Neutron – are neutral, have no electrical charge
Electrons – are negatively charged particles in the nucleus
Atomic number = number of protons
Atomic number – (minus) atomic mass = neutrons
2. Question: Describe the shapes of molecules H2S, CBr4, & PCl3
H2S – bent
Number of bonded atoms: 2
Number of lone pairs: 2
Number of electron sets: 4
Number of bonded atoms: 4
Number of lone pairs: 0
Number of electron sets: 4
PCl3 – pyramidal
Number of bonded atoms: 3
Number of lone pairs: 1
Number of electron sets: 4
3. Question: Calculating types of bonding (ionic, covalent, nonpolar covalent)
Subtract the smaller EN value from the larger EN
value 0 – 0.4 = nonpolar covalent
> (greater than) 0.4 – 1.7 = polar
covalent > (greater than) 1.7 = ionic bond
Ionic bonds – is a bond that forms when electrons is being transferred from one form
to another form, which results in positive & negative ions Covalent bond – a bond
formed when atoms share electrons
Nonpolar covalent bonds – when the EN is very similar between 2
atoms Polar covalent – when the EN is different between 2 atoms
4. Question: Non – polar covalent bonds & polar covalent bonds & electron sharing
Bonding electron pair – the shared pair of electrons in covalent bonds
Nonbonding pairs or lone pairs – the electrons that are not shared as part of
the covalent bond
Nonpolar covalent bonds – when the EN is very similar between 2
atoms Polar covalent – when the EN is different between 2 atoms
, 5. Question: Know the structure & makeup of DNA & RNA, know what DNA
replication, transcription & translation are & ribosomes role in protein synthesis.
Deoxyribonucleic acid (DNA) – provides a mechanism for heredity & serves
as the blueprint for all the proteins of an organism
The DNA helix is held together by hydrogen bonds between
the nucleotides
Adenine (A) binds with Thymine (T) in DNA
Guanine (G) binds with Cytosine (C) in DNA &
RNA DNA complimentary base pairs: A – T; C – G
DNA is made up of genes that code for specific proteins
Ribonucleic acid (RNA) – carries information needed to the protein synthesis
Adenine (A) binds with Uracil (U) in RNA
Guanine (G) binds with Cytosine (C) in DNA &
RNA RNA complimentary base pairs: A – U; C – G
DNA & RNA are polymers of repeating units of nucleotides DNA
Replication – is copying or duplication of DNA molecules Transcription –
the transfer of the DNA gene information to RNA which is transported
out of the nucleus
A segment of DNA called the template str& transfers its
information to a special RNA molecule called messenger RNA
The base sequence of DNA specifies the base sequence of mRNA In
eukaryotes the mRNA is transported out of the nucleus to the
ribosome
Translation – the translation of the mRNA sequence into a specific protein
Decoding of the mRNA results in protein synthesis which occurs in
the ribosome in the cytoplasm of the cell
6. Question: Know what a protein is, its makeup & what is primary, tertiary
(globular), & quaternary structure. Also the types of bonds that holds
the structure together.
Proteins – serve as the structural materials & enzymes of animals
Muscle tissue, skin & hair are mostly proteins
Silk, wool, nails, claws, feathers, horns, & hooves are proteins
Proteins are polymers with the monomer units are about 20
different amino acids
The amino acids differ in their side chains
The structure of proteins have four organizational levels:
Primary Structure – is simply the order of its amino acids; held together by the chain
of amino acids
Secondary structure – polypeptide chains can fold into regular structures within the
protein chain such as alpha chains & beta sheets; held together by alpha helix or
alpha chain which can be many
Tertiary structure – the folded structure of the entire single peptide protein;
single peptide or protein containing alpha helices, beta sheets & more
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