bio Ch. 2

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Terms in this set (...)

Acid
Substance that releases hydrogen ions into a solution, a solution with a pH less than 7
Acidic
A substance that releases hydrogen ions
Antioxidant
a molecule that reacts with free radicals, neutralizing their ability to damage biological molecules.
Atomic number
Number of PROTONS in the nuclei of all atoms of an element
Atomic Nulceus
the central part of an atom that contains Protons and Neutrons
Base
Substance that neutralizes H+ ions, solution with a pH greater than 7
Basic
A substance that neutralizes hydrogen ions
buffer
a compound that minimizes changes in pH by reversibly taking up or releasing H+ ions
chemical Bond
an attraction between two atoms or molecules that tends to hold them together. Types: Covalent, ionic, hydrogen
Cohesion
The tendency of molecules of a substance to stick together
Covalent Bond
a chemical bond between two atoms in which electrons are shared.
Dissolve
When solvent molecules surround and disperse atoms or molecules of another substance.
Electron
Negative subatomic particle, very little mass
Electron Shell
Where an electron orbits
Element
a Substance that cannot be broken down by chemical means
Free Radical
A molecule with an atom with an unpaired electron that steals it from other atoms thereby destroying biological life
Heat of Vaporization
the energy needed to to transform a compound from a liquid to a gas
Hydrogen Bond
a weak attraction between a hydrogen atom with a partial positive charge and another atom
Hydrophilic
Molecules that dissolve easy in water
Hydrophobic
Molecules that do not dissolve easily in water
Hydrophobic Interaction
the tendency of hydrophobic molecules to cluster together in water
Ion
A charged atom or molecule, excess or deficient electrons
Ionic Bond
a chemical bond that is formed by electrical attraction between ions
isotope
one of several forms of a single element, the nuclei of which contain same number of protons but different number of neutrons
Mass Number
Total number of protons and neutrons in an atom
Molecule
a particle composed of one or more atoms held together by chemical bonds, part of a compound.
Neutron
subatomic particle that is neutral in charge and has mass equal to a proton
nonpolar covalent bond
a covalent bond with equal sharing of electrons
pH Scale
a 1-14 scale that measures the acidity of a solution by factors of ten fold change in Hydrogen ions
Polar Covalent Bond
a covalent bond with unequal sharing of electrons
Proton
Subatomic particle with positive charge. mass equal to neutron
Radioacitve
an atom with an unstable nucleus that spontaneously disintegrates and emits radiation
Solution
a solvent containing one or more dissolved substances
Solvent
a liquid capable of dissolving other substances itself
Specific Heat
the amount of energy required to raise the temperature of 1 gram of a substance by 1*C
Surface Tension
the property of a liquid to resist penetration by objects at its interface with the air, due to cohesion between molecules of the liquid.
An Atom consists of an atomic nucleus composed of positively charged __________ and unchanged __________.
Protons & neutrons
The Number of positively charged particles in the nucleus determines the __________ of the element.
Atomic Number
Orbiting around the nucleus are _______________ that occupy confined spaces called _______________.
Electrons & Shells
An atom that has lost or gained one or more electrons are called A(n) ______________.
Ion
If an atom loses an electron it takes on A(n) _____________ charge
Positive
If it gains an electron the atom takes on A(n) ____________ charge.
Negative
Atoms with opposite charges attract one another, forming _____________ bonds.
Ionic
Atoms of the same element that differ in the number of neutrons in their nuclei are called ______________ of one another.
Isotopes
Some of these forms of atoms spontaneously break apart, releasing ____________ particles that carry large amounts of ____________.
Subatomic & energy
In the process, they may become different _____________.
elements
Atoms that behave this way are described as being ____________.
radioactive
An Atom with an outermost electron shell that is either completely full or empty is described as being __________.
inert
Atoms with partially filled shells are ___________.
reactive
Covalent bonds are formed when atoms ____________ electrons, filling their outer shells.
share
Water is described as _____________ because each water molecule has slightly negative and positive poles.
polar
This property allows water molecules to form _____________ bonds with one another.
hydrogen
The bond between water molecules give water a high __________ that produces surface tension.
cohesion