Biology Chapter 2 Flashcards
Any substance in the universe that has mass and occupies space
Matter
Extremely small particles that make up matter
Atom
A positively charged subatomic particle, found in the nucleus of an atom; has a mass of 1 dalton
Proton
A subatomic particle found in the nucleus of an atom, has no charge; has a mass of 1 dalton
Neutron
A negatively charged subatomic particle that orbits around the nucleus of an atom; the mass is 1/2000 of a dalton
Electron
What makes up the nucleus of an atom?
Proton and neutron
What orbits the nucleus of an atom?
electron
what measurement is used for the mass of an atom?
in daltons
How many daltons does it take to equal 1 gram>
6.02 x 10^23 daltons
the number of protons in an atom is called __
atomic number
the sum of neutrons and protons in an atom is called __
atomic mass
any substance that cannot be broken down into any other substance by ordinary chemical means
element
atoms of the same element that have different number of neutrons
isotope
an isotope that is unstable and tends to break up into smaller elements, this decay releases a lot of energy
Radioactive isotope
the rate of decay for a radioactive substance is constant; this is the amount of time needed for 1/2 of the stating material to decay
Half-life
There are ___ naturally occurring elements
92
When an atom or molecule looses an electron
oxidation
when an atom or molecule gains an electron
reduction
How many electrons can be in an orbital?
2
What is an orbital?
the space that an electron occupies
True or False. Energy levels and orbitals are the same.
False
electrons in the outermost energy level are __
valence electrons
Describe the octet rule.
the rule that atoms tend to want to completely fill the outermost energy levels
True or False. For most of the atoms important to life, the outermost energy level can contain no more 8 electrons.
True
Elements possessing all 8 electrons in their outermost energy level is called __ or non reactive
inert
List the noble gases.
helium, neon, argon, krypton, xenon, radon
List the 5 most common elements found in the human body.
Carbon, Hydrogen, Oxygen, Nitrogen, Calcium
atoms where the number of electrons does not equal the number of protons; changing the number of electrons
ions
an atom with more protons than electrons; has a net positive charge
cation
an atom with more electrons; has a net negative charge
anion
a stable association of atoms held together by energy
molecule
a molecule containing more than one type of atom
compound molecule
a bond between atoms resulting from attraction from oppositely charged atoms, or the sharing of one or more pairs of electrons between atoms
chemical bond
a bond resulting from the attraction of oppositely charged ions
ionic bond
a bond resulting from the sharing of one or more pairs of electrons between 2 atoms
covalent bonds
List the different factor that influence the extent of chemical reactions.
Temperature (increases rate), concentrations of reactants & products (more molecules=increase rate), catalyst (enzymes)
are all proteins that are used in the human body in order for a chemical reaction to occur
enzyme
is a measure of the affinity for electrons
electronegativity
Atoms with ___ electronegativity want electrons around them, whereas atoms with ___ electronegativity do not want electrons around them.
high; low
any molecule that has an uneven charge distribution across it
polar molecule
any molecule that has an even charge distribution across it.
non polar molecule
when water molecules stick to other water molecules
cohesion
when water molecules stick to other non water molecules
adhesion
Give an example of cohesion in water properties.
Surface tension- when you have an interface between air and water, all the hydrogen bonds in the water face downward making molecules stick together
Give an example of adhesion in water properties.
Capillary action- the attraction of water to substances that have electrical charges on their surface is responsible`
the amount of heat required to change one gram of substance one degree in water properties
specific heat
the amount of heat required to change one gram of liquid to gas
heat of vaporization
the evaporation of water from a surface releases lots of heat energy, which cools the surface
evaporative cooling
Water is a strong ___ because of its polar nature.
solvent
Either the hydrogen end or the oxygen end in a water molecule will surround any molecule that has any polarity or is ionic, which is called
hydration shell
Property of water- any non polar molecules that are put into water are going to be excluded by the water. This action forces the non polar molecules together.
hydrophobic exclusion
water fearing; does not mix with water; non polar molecules
hydrophobic
water loving; mixes with water; polar molecules
hydrophilic
weight in grams of the sum of atomic masses
mole
concentration of H+ in water is called
molar concentration
a change in the pH value is a __fold change in concentration
10
a pH of 7 is __
neutral
any substance that dissociates in water to increase the H+
acid
any substance that combines with H+ to reduce the H+ in water
base
Acids increase the ___, meaning the molar concentration is __ to the solution, this causes a drop in the __.
H+, higher, pH
a substance that acts as a reservoir for hydrogen ions; prevents changes in pH
buffers
