Unit 2 Flashcards
Electrons are what cause
chemical reactions
electrons can be found in
different energy levels
each energy level corresponds to a
row on the periodic table
Horizontal rows of elements = X = X
period = no. of occupied e- shells
each energy level has what
sub-levels
electrons fill from
right to left
top to bottom
1S^1 what does each stand for
1= energy level S= sub level ^1= # of electron in the orbital
box diagrams
look at college or high school notes
valence electrons
how many does each group have
electrons in the highest energy level
g1= 1, g2=2, g3=3, g4=4, g5=5, g6=6, g7=7, g8=8
just as protons increase across the periodic table, what also increases
electrons
noble gases have how many valence electrons
8
the octet rule ?
atoms are most stable when they have 8 electrons in their valence shell
valence electrons are the
outermost, highest energy electrons
exceptions of the octet rule
H and He
noble gases all have
8 valence electrons
why are noble gases some of the last elements to be discovered
because they do not readily react
octet rule cont. – Atoms will
gain or lose electrons to have 8 valence electrons
atoms will gain or lose electrons to form
ions
what are the types of ions
cations and anions
what are cations
when a neutral atom has a loss of an electron
what are anions
when a neutral atom has a gain of an electron
Ca2+ has what biological important
1.5-2% of body mass, bones, teeth
necessary for blood clotting, digestion, formation of bones and teeth, actions of muscle(heart)
Mg2+ has what biological important
bones and teeth, intracellular activity
Fe2+ has what biological Important
neccessary for formation of hemoglobin and cytochromes, O2 transfer
Cu2+ has what biological important
cofactor in enzymes
Zn2+ has what biological important
cofactor in enzymes, growth, healing
Co3+ has what biological important
in vitamin B12
Na+ and K+ has what biological important
water balance, nerve impulses, fluids inside and outside cells
Na+= extracellular positive ion
K+ Intracellular positive ion
cations ??
lose electrons
become more positive
cation elements are written
with symbol and a #+ or +# to the upper right
In Cations you must indicate
how many electrons have been lost
cations are named
as “element name and ion”
some metals can lose different
of electrons
transition metals, you must include
charger
ions, some metals
can lose different # of electrons
Anions ??
gain electrons
they become more negative
which nonmetals will become anions
nonmetals in groups 5,6,7
which metals will become cations
metals in groups 1,2,3
group 4 is iffy
in anions, you must indicate
how many electrons have been gained
Anions are named
as “element name ending in -ide and ion”
prediction Ion charges?? what are they
G1= 1+ G2=2+ G3=3+ G4=4+- G5=3- G6=2- G7=1- G8=0
polyatomic ions
sometimes groups of atoms bounded together will have a overall net charge
what does it mean to be an isoelectronic atom
they have the same electron configuration
during lewis dot structures, valence electrons
can be depicted as dots around the element symbol
lewis dot structures can be used to
predict bonding behavior in atoms
what are the 3 types of bond
ionic bond, polar covalent, and nonpolar covalent
what are ionic bonds
give and take electrons
metals with nonmetals
what are nonpolar covalent bonds
nonmetals with nonmetals
share electrons equally
what are polar covalent bonds
nonmetal with nonmetal
share electrons but not equally
why do nonmetals have high electronegativty
nonmetals are negative and pull electrons towards them which means high electronegativity
what is the electronegative difference for pure covalent
<0.4
what is the electronegative difference for polar covalent
between 0.4 & 1.8
what is the electronegativity difference for ionic bond
> 1.8
how do elements combine
atoms can donate or accept valence electrons to reach 8 VE-
atoms will bond together this way forming ionic bonds
naming ionic compounds found in S or P orbitals
write the periodic table name for the cation
write the name of the anion 2nd, but change the last 3 letters of the anions name to “ide”
DO NOT WRITE ANY NUMBERS WITH THE NAMES
naming ionic compounds found in D orbitals
write the periodic table name for the cation
after the cation is written, write the roman numeral for the ion’s charge in partentheses
write the anion 2nd and change the ending to “ide”
NO OTHER NUMBERS NEEDED
Naming with polyatomic ions
write the periodic name for the cation(make sure if D orbital roman numeral is there)
write the anion 2nd, no changes to name –write it how it is on the polyatomic ion sheet
IF THE 2ND ION IS ON THE PERIODC TABLE, CHANGE THE ENDING TO “IDE”
Writing ionic compounds
total charges need to= total-charges
or + and - need to add up to 0
number of each element is included as a subscript
cation 1st, anion 2nd
On the polyatomic ion sheet, most of them have what in it
oxygen (known as oxyanions)
writing ionic compounds w/polyatomic ions
write the cations name, no changes to name 1st
name anion 2nd - use polyatomic name
in covalent bonds, no what are formed?
no ions are formed=no charges to balance
writing covalent compounds
element farthest to the left is written first
elements to the right are written 2nd, 3rd, 4th, etc.
subscripts are used to indicate how many of each element are present
last element name ends in “IDE”
naming covalent compounds - numerial prefixes
mono-1 di-2 tri-3 tetra-4 penta-5 hexa-6 hepta-7 octa-8 nana-9 deca-10 last element name ends in "IDE"
a mol in chemistry is
a way of quantifying or counting atoms & molecules
a mol relates
the mass of elements to numbers of atoms it contains
how do we count atoms and molecules in moles
by avogrado’s number
what is avagadros number
6.02 X 10^23
One mol of an element is equal to what
equal to its atomic mass in grams
one mol of a compound is equal to what
equal to the sum of its atom’s atomic masses in grams
for mole coversions, we only need to know what 2 things
molar mass and avagadros #
mass cannot be
created or destroyed
the coeffiants represent what in a balanced equation
represent mole ratios
mole ratios can be used to convert to
mass or molecules
mole conversions steps
balance equation
find molar mass of what you have
find molar mass of what you need
use coefficants and dimensional analysis to solve
not all covalent bonds are created
equal
chemical bonding are used in
correct dosages
dru g interactions
how compounds react with the body, cells, tissues and organs
some(most) covalent bonds include
unequal sharing of electrons
electronegatvity def
the ability to attract electrons
as you go from left to right, your electronegativity
as you go from bottom to top, your elecrtonegativity
L to R = increase
bottom to top=increases
polar covalent bonds
unequal distribution of electrons
dipole movement
dipole movement has a magnitude and a direction
nonpolar covalent bonds
equal distribution of electrons
determining polarity step 1.
1) is the molecule a hydrocarbon?
no- determine the molecules lewis structure
yes- molecule nonpolar
determining polarity step 2.
2) determining the molecules shape
determining polarity step 3.
3) is my shape symmetric
no- molecule polar
yes- examine outside atoms
determing polarity step 4.
4) if the shape is symmetric, are all outside atoms the same
no-molecule polar
yes-molecule is nonpolr
the polarity is due to the
lone pair on the central oxygen atom
what is molecular geometry
electrons are negatively charged
they repel eachother
electron orbitals repel eachother
it is the outermost or valence electrons that interact
NEED TO KNOW
think of atoms like balloons– they pull??
eachother apart at maximum angles
we use lewis dot diagrams to
represent valance electrons to predict the shape of molecules
what does VSEPR stand for
valence shell electron pair repulsion
what is the VSEPR theory
predicts geometry of molecules based on electron repulsions
each pair of electron pair counts as
one electron domain
double and triple bonds count as
one electron domain
