Week 2 Flashcards
atoms
basic (smallest) structural units of elements
elements
substance that cant be broken donw into simpler substance
chemical rxn
processes that form/break bonds between atoms
periodic table
organizes elements according to atomic #/chemical characteristics
atoms are made up of __ subatomic particles
3 (neutrons/protons/electrons)
__ are found in the inner most core (nucleus) of the cell
protons/n`eutrons
of protons should
equal # of electrons
atomic # will ..
always equal # of protons
mass #
sum of protons + neutrons
merucry causes __ nerve cells
denuded nerve cells
isotopes
atoms of elements w/ diff # of neutrons
- each has diff mass # of neutrons
radioactive
nuclei spontaneousl break part (releases energy)
nuclei provide stability by
remaining uncharged (the protons/neutrons) during chem rxn
electeons are repsonsible for
interactions among atoms
the electrons close to the nucleus are
low energy and inner-most shell can only carry 2 electrons
the electrons in the outermost shell are
high energy
electron absorbs energy from sunlught, uv rays, etc..
is then boosted to a higher shell, then drops back into lower enery shell and then releases energ as heat and light (like bioluminescence)
molecules
made up of 2 or more atoms
atoms form molecues to
fill vacancies in outer electron shells
atom wont react w/ other atoms …
if outermost shell is full
(these are called inert (stable) atoms)
__ is highly electronegative
oxygen (lieks taking electrons from other atoms)
free radicals
atom whose outermiost shell is partially full (can contribute to aging/death since they can be so reactive)
__ bonds hold atoms together in molecules
chemical
chemical bonds
attract forces that hold atoms together (atoms gain/lose/share electrons)
ionic bonds
attraction where electron is transferred ex: salt (NaCl)
covalent
electrons are shared between atoms
nonpolar covalent
electrons shared equally betwen atoms ex: CO2/ ex: hydrogen atom + hydrogen atom
- are also less likely to dissolve
polar covalent
electrons are shared unequally ex: H2O
hydrogen bonds
attraction between polar nolecules where hydrogen is bonded to olxygen/nitrogen
- these bonds are very weak and can break when heat is increased!
octet rule
8 electrons in outer shell
ex: table salt is ionic
hydrigen bonds in water cause
cohesion
cohesion
tendency of water molecules to stick together ‘
- also produces surface tension
surface tension
tendency for water molecule to resist being broken
water has __ prpoerties
cohesive/adhesive
- water will move up a root of a plant due to cohesive properties (capillary action)
mercury has __ forces but not __
cohesive but not adhesive, which is better for a thermometer
blood is both __ and __
cohesive/adhesive has lots of water
water is a very important ..
solvent
oil/water dont mix cuase of
nonpolar electrons
pH
power of Hydrogen
Water breaks down into
hydroxide/hydrogen ion
hiw to say the pH of a solution:
the concentration of H+ ions versus the amount of OH- ions
acidic solution
H+ excees OH-
-an acid releases H+ when dissolves in water
ex: lemon juice
basic solution
OH- exceed H+
- a base increases OH- solution when dissolved in water
ex: socium hydroxide separates into both sodium and hydroxide in water
neutral solution
equal balance between H+ and OH-
ex: water (pH is 7)
blood/milk are neutral to an extent
- blood = 7.4
- milk = 6.4
