BIOL 1103K: Chapter 2 Test Review

CourseStructure object (98339) - Georgia State University

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22 Cards in this Set

Front	Back
atoms	basic structural units of elements, composed of subatomic particles: protons (+) and neutrons (0) in the nucleus and electrons (-) orbiting in shells
ion	a charged atom
How many electrons can the first shell of any atom hold?	two
How many electrons can an atom's outer shell (not the first one) hold?	eight
What does the atomic number of an atom represent?	The number of protons and electrons
If oxygen has an atomic number of 8, how many electrons are in its outer shell?	six (the other two are in the first shell)
ionic bond	occurs when an electron is transferred between atoms, creating positive and negative ions that attract each other, ex. Na+ and Cl- form NaCl (table salt)
covalent bond (general)	occurs when electrons are shared between atoms
nonpolar covalent bond	occurs when electrons are shared equally between atoms, ex. two H atoms form H2
polar covalent bond	occurs when electrons are shared unequally between atoms, ex. between H and O in H2O
hydrogen bond	occurs between polar molecules when H is bonded to O or N, ex. between water molecules
Polar bonds are hydro_, while nonpolar bonds are hydro_.	philic, phobic
Water is an effective solvent because...	H2O molecules are polar and can therefore disrupt ionic bonds
water-soluble	breaks apart readily in water due to being hydrophilic
hydrophilic	"water-loving," breaks apart readily in water
hydrophobic	"water-fearing," repulsed by water and clumps together in its presence
How does sweating keep our bodies cool?	The water in sweat absorbs a large amount of heat and evaporates.
Water (expands/contracts) when it freezes.	expands
acid	a solution in which there are more H+ ions than OH-; pH is less than 7
base	a solution in which there are more OH- ions than H+; pH is greater than 7
buffer	a type of molecule that helps a solution maintain constant pH by accepting or releasing H+ in response to a pH change, ex. bicarbonate (HCO3-)
Why do antacids calm an upset stomach?	They are basic and neutralize excess stomach acid.