Chemistry Ms19-25 Flashcards
define atom
the smallest unit of matter
define atomic nucleus
where protons and neutrons are located
define electron
negatively charged subatomic particle known as “e-“; has negligible mass
define neutron
neutrally charged subatomic particles located in nucleus
define proton
positively charged subatomic particles located in nucleus
define orbital
path that e- follows
how to find Atomic Mass?
protons+neutrons
what are protons equal to?
atomic #
define valence shell
of the outer shells where electrons bond
where are higher energy levels?
higher energy levels are found farther from nucleus
what is matter?
has makes and takes up space
what is an element?
a pure substance made up of only one kind of atom with a characteristic number of protons
what is an isotope?
a variation on the the element that has the same number of protons but a different number of neutrons, changing its mass
what is an ion?
an atom that is positively (cation) or negatively charged(anion)
what is a molecule?
2 or more atoms covalently bonded together
what is a compound?
different atoms chemically bonded together
what is atomic mass?
of protons and neutrons in an atom
what is atomic #?
that tells us how many protons are in an atom
how do you find the number of protons in an element?
the atomic number is equal to the number of protons
find the number of e- in an element?
same as the number of protons
how do you calculate the number of neutrons in an element?
atomic mass - atomic number
how do you determine the number of e- in the valence shell?
use family number (column)
names of groups and elements?
alkaline earth, alkaline, transition, halogens, noble gases
which elements make up 96% of organic matter?
carbon, hydrogen, nitrogen, oxygen
an atom is mostly made up of what?
space
how many e- can fit in an orbital?
2
changing an atoms number of protons =
a different element
changing an atoms number of neutrons =
isotope
changing the number of electrons =
ion
what is a cation
positive
what is an anion
negative
what is Thomson’s plumb pudding model do?
hypothesis about atomic structure
what is Rutherford’s gold foil experiment?
hypothesis that an atom is mostly space
what do columns share on the periodic table?
the same number of valence shell e-
what are rows arranged by?
energy levels
how are energy levels filled?
lowest first
how are S orbitals shaped and how many are there per energy level?
spherically shaped, 1 per energy level
how are P orbitals shaped and how many are there per energy level?
dumbbell shape, 3 per energy level
how are D orbitals shaped and how many are there per energy level?
clover shaped, 5 per energy level
when are there S P and D orbitals?
energy level >= 4
what is the max number of electrons per energy level when n> 2
18 electrons
how do orbitals filled?
sequentially; lowest to highest
n^2 =?
of orbitals per energy level
2n^2= (2)
of electrons per energy level
the octet rule?
atoms like to fill S and P orbitals in order to try to achieve noble gas state
where are valence electrons found?
where the orbitals are the farthest out
what is the reactivity level of elements close to a noble gas configuration?
Highly reactive
what is the reactivity level of noble gases?
stable
what is Hund’s rule?
electrons occupy orbitals singly before they pair, from left to right
what is a Lewis Dot Structure used for?
used to predict/show chemical bonds
what elements are in covalent bonds?
non-metal + non-metal
what elements are in ionic bonds?
metal + non-metal
what do covalent bonds produce?
molecules
what do ionic bonds produce?
salts
how do you break bonds?
absorption of energy
how do you from bonds?
release of energy
what is exothermic reactions?
a reaction that releases more energy than it absorbs
what is endothermic reactions?
a reaction that absorbs more energy than it releases
what is a mole
a unit of measurement for an amount of a substance
the number of atoms in a mole is the same but the ___ can vary
mass
Conversion chart for moles to grams?
grams of substance over moles of substance is equal to molar mass of the substance in grams over one mole
What is molar mass?
the sum of each atom’s atomic mass
What operation do you use for g to mol? For mol to g?
g to mol is division while mol to g is multiplication
H2O is a very good medium for what?
chemical reactions
what percentage of cells are water?
70%
when do cells shutdown?
when water percentage is lower than 50%
what is a polar molecule?
e- shared unevenly across covalent bonds, resulting in partial charges at the poles of the molecule
what is electron negativity?
e- grabbing/hogging power of an atom (unbalanced)
what does electron negativity cause?
e- are pulled towards atoms w/higher electron negativity
when do you have no electronegativity?
with the same atom (&covalent bonds)
why is H2O bent?
H atoms are pushed away from O atom because of electron negativity
what charge does the atom(s) that is pulling the e- to it have
slightly -
what charge does the atom(s) that is having their e- pulled?
slightly +
what results in molecule to molecule attractions?
Polarity
what are hydrogen bonds in terms of power?
weak alone powerful together
what is the gas state of H2O like?
H bonds form/break quickly; molecules farther apart
what is the liquid state of H2O like?
denser than solid; H bonds form/break less quickly; molecules tightly packed together
what is the solid state of H2O like?
H bonds form in geometric pattern(crystal lattice), pattern results in larger spacing between molecules than liquid form; solid
what is molarity?
a unit of concentration
if you have higher molarity you have higher____?
concentration
how to find molarity chart?
molarity is equal to number of moles of solute divided by Liters of solute
H2O is a __ solvent?
universal
what does it mean that H2O is a universal solvent?
forms H bonds w/ other polar substances(salts)
what does a hydration shell form around, and what do they do?
forms around ions and other polar substances breaking solids down into individual molecules through dissolving
why does heat speed up dissolving?
because H20 molecules are moving quicker w/ a higher kinetic energy level
“solution” arrows
solvent—> solute—–> solution
what is solubility?
how well a substance dissolves in a solvent
what does water do (connections)?
adhesion and cohesion
what is adhesion
surface connection
what is cohesion
self connection (like)
what is the difference of water on a polar vs. non polar surface?
wide on polar; tight on non polar
what kind of bond is cohesion?
H bond
what does spherical curvature do?
maximizes H20 cohesion and adhesion
what is heat capacity?
amount of heat required to raise a substances temperature 1 degree celsius (H2O’s is exceptionally high)
example of H20 heat capacity?
ocean. 80-90% of heat absorbed in ocean without significant rise in temperature
what are colligative properties? & example
amount of solutes dissolved in H20 alters its properties; antifreeze in water keeps it from freezing with a high concentration of solutes
what do fish produce to lower the freezing point of their blood?
proteins that dissolve into the blood
