Chapters 2&3 Flashcards
Describe the general structure of atoms
Protons and neutrons are in the nucleus
Electrons are in orbit around the nucleus
Define orbital and electron shell
Orbital - the region surrounding the nucleus of an atom and the probability of finding an electron is high
Electron shells are the energy levels; larger atoms have more electron shells than smaller atoms
Relate atomic structure to the periodic table of the elements
The number of protons and electrons determine an atom’s position on the periodic table.
Explain how elements can exist as isotopes
Elements that have a different number of neutrons than protons is considered an isotope
Compare and contrast ionic, covalent, and hydrogen bonds; atomic interactions that lead to the formation of molecules
Ionic bonds - happens when an atom or molecule gains or loses one or more electrons and acquires a net charge
Covalent bonds - chemical bond where two atoms share a pair of electrons
Hydrogen bonds - a weak interaction between a hydrogen atom in a polar molecule and an electronegative atom in another polar molecule
Explain the concept of electronegativity and how this contributes to the formation of polar and nonpolar covalent bonds
Electronegativity is the measure of an atom’s ability to attract electrons in a bond with another atom. Atoms that have fuller valance electron clouds (O,N, F) do not like to share the electrons, so they take them majority of the time and rarely return them. This creates polar and nonpolar bonds.
Nonpolar - strong covalent bond formed between 2 atoms with similar electronegativities and the electrons are shared
Polar - a covalent bond between 2 atoms with different electronegativities. FON
Identify the properties of water that support life
Can provide force or support for the bodies of organisms and plants
can remove toxic waste compounds from animal’s bodies
Distinguish between hydrophilic and hydrophobic substances
hydrophilic - water loving
Hydrophobic - water hating
Relate the concept of electronegativity to hydrophilic and hydrophobic substances
Similar to electronegativity, hydrophilic substances have a strong pull towards water and create strong bonds like nonpolar.
what is matter?
Anything that has mass and takes up space
Element
a pure substance made up of one atom
Atom
smallest functional units of matter that form all chemical substances and ultimately all organisms
Proton, electrons, and neutrons. What are they
proton - positive particle found in nucleus and determines the atomic number that defines each element
Neutrons - neutral particle found in the nucleus
Electrons - negative particle found in orbitals around nucleus
Orbital
Electron Shell
Valence Electron
Electron cloud
Orbital - region surrounding the nucleus where electrons are found
Electron shell - energy level
Valence electron - electrons in the outermost shell
Electron cloud - general term when referring to the location of the electrons
Ion
when an atom or molecule loses or gains one or more of its valence electrons
Isotopes
when the neutron count differs from proton count
Electronegativity
a measure of an atom’s ability to attract electrons in a bond with another atom
Solvent
liquid in which the solute is dissolved
Solute
A substance dissolved in a liquid
Density
mass of a unit volume of a material substance
ice is less dense than water = floats on top
Equilibrium
Basically when the equation is balanced
- A state of a chemical reaction in which the rate of formation of products equals the rate of formation of the reactants
Reactant
A substance that participates in a chemical reaction and becomes changed by that reaction
Product
End result of a chemical reaction
Chemical Reaction
A process in which one or more substances are changed into other substances by the making or breaking of bonds
Covalent bond
A chemical bond where two atoms share a pair of elections, whether fairly or unfairly
Polar molecule
have one or more polar covalent bonds
Van der Waals interaction
Attractive forces between molecules in close proximity to each other, caused by the variations in the distribution of electron density around individual atoms
- results from small differences in electron clouds in nonpolar bonds
- between nonpolar molecules
- very weak but collectively strong
Hydrogen Bond
A weak interaction between a hydrogen atom in a polar molecule and an electronegative atom in another polar molecule
Hydrophobic vs. Hydrophilic
Hydrophobic is water hating
hydrophilic is water loving
Why are valence electrons important?
Valance electrons are the part of the atom actually participating in bonding
Why is water so important? How does it accomplish this?
Water is the solvent for most chemical reactions in all living organisms, inside and outside of cells. Hydrolysis reactions break down large molecules into smaller units. Water provides support, eliminates wastes, dissipates body heat
Are hydrogen bonds typically within or between molecules
between
If Van Der Waals forces are so weak, why are they important? Give a couple examples
They allow nonpolar molecules and atoms to become solids and liquids and are responsible for surface tension, which allows for bugs to walk on water
Grease is hydrophobic. How does soap help to remove grease form your hands?
The soap has both polar and nonpolar ends, so the hydrophobic ends of the soap molecules attract the grease, form a drop around the grease (ball) and then allow the oil ball to roll off the skin
Compare and contrast covalent and ionic bonds
Covalent is when they share electrons, whether fairly or unfairly. Ionic is when the atom/molecule actually loses or gains an electron
Why are some covalent bonds polar and some covalent bonds non-polar?
It depends on if the atoms/molecules are sharing the electrons fairly. If they are, the bonds are nonpolar. However, if one atom is hogging the electrons (has a higher electronegativity), then the bond is polar
A polar covalent bond is created when
a. electrons transferred from one atom to another disrupt the balance between the
two sides of the bond, making the bond very unstable.
b. bonded atoms have an equal pull on the shared electron so that the electron
spends approximately equal amounts of time around each.
c. bonded atoms have unequal pull on the shared electron so that the electron
spends more time around one atom than the other.
d. electrons and protons are shared between atoms, creating a strong bond, which
can only be broken with a large input of energy
c
Carbon and hydrogen have similar electronegativities and combine together to form
hydrocarbon molecules. What type of bonds form between these atoms?
a. hydrogen
b. ionic
c. polar covalent
d. nonpolar covalent
e. electrostatic
c
What type of bonds form from the unequal sharing of electrons?
a. hydrogen
b. ionic
c. polar covalent
d. nonpolar covalent
e. electrostatic
c
The LEAST hydrophilic substance is
a. salt.
b. an ion.
c. oil.
d. an amphipathic molecule.
c
Define an organic molecule.
A carbon-containing molecule, so named because such molecules were first discovered in living organisms
Identify common functional groups of organic compounds
functional group - a group of atoms with a characteristic chemical structure that exhibits particular properties
Amino (-NH2)
Carbonyl Ketone (-CO)
Aldehyde (-CHO)
Carboxyl (-COOH)
Hydroxyl (-OH)
Methyl (-CH3)
Phosphate (-PO4^2-)
Sulfate (-SO4^-)
Sulfhydryl (-SH)
Explain the roles of dehydration and hydrolysis reactions in the formation and breakdown of organic molecules
Hydrolysis reaction - When a polymer is broken down into monomers by water because each monomer is replaced by a molecule of water
Dehydration reaction - a type of condensation reaction where water is lost (a molecule of water is removed when a monomer is added to a growing polymer)
List the four main classes macromolecules of cells
Carbohydrates, lipids, proteins, and nucleic acids
Compare and contrast the structures of carbohydrates, lipids, proteins, and nucleic acids
Carbohydrates - (CnH2On) *n is a whole number
Lipids - primarily composed of carbon and hydrogen, with some oxygen; can have phosphorous (phospholipids, steroids, & waxes); hydrophobic
Proteins - a polypeptide (or more) composed of a linear sequence of amino acids
Nucleic acids - linear sequence of nucleotides (DNA is double-stranded; RNA is single-stranded but may have double-stranded regions)
Describe the different functions of carbohydrates in cells
- supply energy to all cells in the body
- build macromolecules
- Assists in lipid metabolism
Sugars, small carbohydrates, are broken down by enzymes, which releases energy
List the classes of lipid molecules important in living organisms
Triglycerides - made from glycerol and three fatty acids (fatty acids - chain of carbon and hydrogen atoms with a carboxyl group [-COOH])
Phospholipids - similar to triglycerides except the third hydroxyl group of glycerol is linked to a phosphate group rather than a fatty acids
Steroids - four fused rings of carbon atoms form the general structure of all steroids
Waxes - contain one or more hydrocarbons and long structures that resemble a fatty acid attached by its carboxyl group to another long hydrocarbon chain