Anatomy- Chapter 2

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chemical element
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Terms in this set (68)
chemical element
all forms of matter- both living and nonliving- are made up of a limited number of building blocks
atoms
smallest units of matter
subatomic particles
protons neutrons and electrons
mass number
sum of protons and neutrons
Isotopes
atoms of an element that have different numbers of neutrons and therefore different mass numbers.
Dalton
-atomic mass unit (also known as)
-standard unit for measuring the mass of atoms and their subatomic particles
atomic mass
the average mass of all its naturally occurring isotopes
Ion
an atom that has a positive or negative charge because it has unequal numbers of protons and electrons
Ionization
the process of giving up or gaining electrons
molecule
when two or more atoms share electrons
compoundsubstance that contains atoms of two or more different elementsfree radicalan atom or group of atoms with an unpaired electron in the outermost shell.chemical bondsforces that hold together the atoms of a molecule or a compoundvalence shellthe number of electrons in the outermost shellOctet Ruletwo or more atoms that interact in ways that produce a chemically stable arrangement of either valence electrons for each atom.Ionic Bondthe force of attraction that holds together ions with opposite chargesCationpositively charged ionAnionnegatively charged atomelectrolytean ionic compound that breaks apart into positive and negative ions in solutioncovalent bondtwo or more atoms share electrons rather than gaining or losing hemsingle covalent bondwhen two atoms share one electron pairdouble covalent bondresults when two atoms share two pairs of electronstriple covalent bondtwo atoms share three pairs of electronsnonpolar covalent bondtwo atoms share the electrons equally one atoms does not attract the shared electrons more strongly than the other atom.polar covalent bondthe sharing of electrons between two atoms is unequal--the nucleus of one atom attracts the shared electrons more strongly than the nucleus of the other atom.electronegativitythe power to attract electrons itselfhydrogen bond-result from attraction of oppositely charged parts of molecules -weak compared to covalent and ionic bonds -happens when a partially negative charged hydrogen atom attracts a partially positive charged atomsurface tensiona measure of the difficulty of stretching or breaking the surface of a liquid.chemical reaction-occurs when new bonds form or old bonds break between atoms -foundation of all life processesreactantsstarting substances- two H2 and one O2productsending substances--two molecules of H2OIn a chemical reaction...-the total mass of the reactants equals the total mass of the products -the number of atoms in each element is the same before and after the reactionmetabolismall the chemical reactions occurring in the bodyenergyis the capacity to do workpotential energyenergy stored by matter due to its positionkinetic energythe energy associated with matter in motionExample for potential and kinetic energythe energy stored in water behind a dam or in a person poised to jump down some steps is potential energy. When the gates of the dam are opened or the person jumps, potential energy is converted into kinetic energychemical energy-form of potential energy that is stored in the bonds of compounds and molecules. -total amount of energy present at the beginning and end of a chemical reaction is the same.Law of conservation of energy-although energy can be neither created nor destroyed, it may be converted from one form to another.overall reactionmay either release energy or absorb energyexergonic reaction-ex-out -release more energy than they absorbendergonic reaction-end- within -absorb more energy than they releaseactivation energy-a sufficiently forceful collision can disrupt the movement of valence electrons, causing an existing chemical bond to break or a new one to form. -the collision energy needed to break the chemical bonds of the reactantsconcentration of particles-more particles of matter present in a confined space, the greater the chance that they will collide. -concentration of particles increases when more are added to a given space or when the pressure on the space increases, which forces the particles closer together so that they collide more often.temperature influencing the chance that a collision will occur and cause a chemical reactiontemperature goes up, particles move more rapidly -the higher the temperature of matter, the more forcefully particles will collide, and the greater the chance that a collision will produce a reaction.Catalysts-chemical compounds that speed up chemical reactions by lowering the activation energy needed for a reaction to occur. -most important catalysts in the body are enzymesFor chemical reactions to occur...some particles of matter--especially large molecules--not only must collide with sufficient force, but they must hit one another at precise spots. A catalyst helps to properly orient the colliding particles.synthesis reaction-when two or more atoms, ions, or molecules combine to form new and larger molecules. -synthesis means "to put together"anabolism-all synthesis reactions that occur in the body are referred to as anabolism -usually endergonic because they absorb more energy than they releasedecomposition reactions-split up large molecules into smaller atoms, ions, or molecules.Catabolism-decomposition reactions that occur in your body -usually exergonic because they release more energy than they absorb.exchange reactions-consist of both synthesis and decomposition reactionsreversible reactionthe products can revert to the original reactants.oxidationrefers to the loss of electrons; substance releases energyreductiongain of electrons; reduced substance gains energyoxidation-reduction reactionsalways parallel; when one substance is oxidized, another is reduced at the same time.inorganic compoundsusually lack carbon and are structurally simple.organic compoundsalways contain carbon, usually hydrogen, and always have covalent bonds.watermost important and abundant inorganic compound in all living systems.solvent-dissolves another substance (solute) -ex. watersolute-substance being dissolved -ex. sugarhydrophilic-solutes that are charged and contain polar covalent bonds -^they dissolve easily in water -examples sugar and salt -Hydro=water, ophilic= lovinghydrophobic-molecules that contain mainly nonpolar covalent bonds. -phobic= fearing -they are not very water soluble -examples are animal fats and vegetable oilshydroplysis-lysis= to loosen or break apart -enable dietary nutrients to be absorbed into the bodydehydration synthesis reaction-de= down, hydra= water -a water molecule is one of the products formed. -two smaller molecules join to form a larger moleculeThermal properties of water-heat capacity -heat of vaporizationmixturea combination of elements or compounds that are physically blended together but not bound by chemical bondscolloiddiffers from a solution mainly because of the size of its particles