Chemistry Test 2
For degenerate orbitals, the lowest energy state is attained when the number of electrons with the same spin is maximized. So for a degenerate set of orbitals, one electron goes into each orbital until all the orbitals of the subshell are half-filled. Once all the orbitals of the subshell are half-filled the pairing of electrons can take place.
Hund's rule
transferred
IN AN IONIC BOND, the electron is essentially _______________ from one atom to another atom
the metal transfers its valence electrons to the nonmetal
In Ionic Bonding
polar
In general, the greater the electronegativity difference between the bonding atoms, the more ______ the bond.
terminal (at the ends)
In lewis structures, Hydrogen atoms are always _________
the energy ordering of the orbitals. Hydrogen atoms: Energy of orbital only depends on n (3s, 3p, 3d orbitals) all have the same energy (degenerate) Orbitals within a principle of a multi- electron atom: are no degenerate- energy relies on l within a principal level. Thus given value of n: E(s orbital)<E(p orbital)<E(d orbital)<E(f orbital) (THE LOWER VALUE OF L WITHIN A PRINCIPAL LEVEL, THE LOWER THE ENERGY OF ORBITAL)
What is the major difference to the Shrodinger equation for multi-electron atoms compared to the orbitals for the hydrogen atoms
no two electrons in an atom can have the same four quantum numbers, each orbital can have a max of only 2 electrons with opposing spin
What is The Pauli Exclusion Principle?
same shape, 2s larger in size and has more nodes
2s vs 1s
4p
3p or 4p farther from nucleus
the 4d, 5d, 6d, etc orbitals are similar in shape to the 3d orbitals, but they contain additional nodes and are progressively larger in size
5,5,6 d orbitals vs 3d
Bohr model: in lowest energy state, electron had this radius QM model: electron at various radii, 52.9 had greatest probability
52.9 pm
probability distribution map that shows where the electron is likely to be found
What is a quantum mechanical orbital
the future path of an electron is indeterminate and can only be described statistically- can have probability distribution map though
What is indeterminacy- describe it in terms of electrons
single electrons interfering with themselves
What is the electron interference pattern caused by
polar covalent bond
A covalent bond in which electrons are not shared equally intermediate in nature between a pure covalent bond and an ionic bond
orbital (probability distribution map showing where the electron is likely to be found)
When the electron's position can be specified, the location has to be specified as an _________
principle (n)
Which of the following quantum numbers describes the size and energy of an orbital?
less than
With like V2+, the 4s would lose electrons before 3d because 4 is greater than 3
removal
______ of successive electrons always requires more energy (e.g., Ei3>Ei2>Ei1) because a negative electron is being removed for a successively higher positive charge.
100% (although even the most ionic bonds do not reach this ideal
a bond in which an electron is completely transferred from one atom to another would have a ________ ionic character
the relative quantities of each element in a compound
a chemical formula, in combination with the molar masses of its constituent elements, indicates ___________
orbital diagram
a diagram that shows the distribution of electrons in the orbitals of the energy levels
Main group elements: Valence electrons is group number polyatomic ion: add one electron for each negative charge and subtract one electron for each positive charge
How to determine electrons for Lewis structures
bonding pair lone pair (nonbonding electrons)
a shared pair of electrons is called a _________ whereas a lone pair of electrons is called a _______
space-filling molecular model
atoms fill the space between each other to more closely represent our best estimates for how a molecule might appear if scaled to visible size
ratio of masses
empirical formula represents a ratio of atoms or ratio of moles of atoms, not a _______
Body's natural pain killers
endorphins
its lettered group number
except for helium, the number of valence electrons for any main group element is equal to _____
He : stable because n=1 quantum level fills with only 2 electrons
exception to lewis structure : helium
Cr: 4s13d5 Cu: 4s13d10
exceptions of electron configurations
boron: smaller ionization energy than beryllium (caused by the change in going from the s block to the p block)
exceptions to ionization energy?
sharing or transfer of electrons to attain stable electron configurations for the bonding atoms
in the lewis model, a chemical bond is the _________________
terminal, central
in the lewis structures, put the more electronegative elements in the _______position and less electronegative elements in the _________ position
n (principal quantum number) l (angular momentum quantum number) ml (magnetic quantum number) ms (spin quantum number)
n? l? ml? ms?
naming compounds
nomenclature
represents the radius of an atom when it is not bonded to another atom
non bonding radius (van der Waals radius)
which depicts neighboring atoms sharing some or all of their valence electrons in order to attain octets
the Lewis structure represents covalent bonding...
magnitude
the ______ of the potential energy depends inversely on the separation of charged particles
count towards the octet of both atoms double bond- when two atoms share electron pairs (stronger) the double bond on oxygen explains why its a diatomic molecule
the additional bonding pairs____
atomic radii
the approximate bond length of any two covalently bonded atoms is the sum of their ______
the orientation of an electron's spin
the arrows in an orbital diagram represent_____
all electrons in outermost shell and any partially filled D of F sub-shells
valence electrons
l = 0, s l = 1, p l = 2, d l = 3, f
value of l / letter designation
entirely new substance results
when two or more elements combine to form a compound, an ________________
nodes
where the wave function, probability density (wave function squared), and radial distribution function all go through 0 probabilty of finding an electron at a node is _______
angular (l)
which quantum number describes shape of orbital
they are held the most loosely and therefore easiest to lose or share
why are valence electrons important for chemical properties
because 4s orbitals more efficiently penetrate into the region occupied by core electrons
why do 4s orbital fill before 3d orbitals
they are instrumental in bonding because they are held the most loosely (easiest to lose or share)
why do the chemical properties of an element depend on valence electrons?
lowest
electrons generally occupy the __________ energy orbitals available
90
electrons have a ______ percent chance of being in the different estimated orbitals
THE FIRST ELEMENT
emit the mono if there is only one atom of
core electrons
electrons in complete principal energy levels and those in complete d and f sublevels
in grams
ALWAYS REMEMBER the chemical formula gives us the relationship between the amounts(in moles) of substances , not between the masses (_________) of them
increase
According to Coulomb's law, the attraction between a nucleus and an electron _______ with increasing magnitude of nuclear charge.
True
An orbital that penetrates into the region occupied by core electrons is less shielded from nuclear charge than an orbital that does not penetrate and therefore has a higher energy
cation
As electrons are removed from an atom, the remaining electrons are pulled closer to the positively charged nucleus. Conversely, if electrons are added to an atom, the nucleus becomes less efficient in attracting a larger number of electrons. For a given atom, which species would likely have the smallest radius?
Trajectory is determined by position, velocity, and forces acting on the thing. So, we cannot know an electrons trajectory (no position or velocity can be observed together)
Can trajectory of an electron be measured? Why?
lower, charged
Chemical bonds form because they ____ the potential energy of the _____ particles that compose atoms.
random
Chemical formulas indicate the ratios of the different types of atoms in a compound. Percentage composition indicates the relative masses of each element in a compound. Mass ratios are important for lab work, and atomic ratios are important for understanding chemical reactions.
valence electrons
Chemicals in the same column have the same chemical properties because they have the same number of...
all electrons in inner energy levels including completely filled D and F sub-shells
Core elecrons
do not efficiently shield one another from nuclear charge
Core electrons efficiently shield electrons in the outermost principal energy level (highest n) from nuclear charge, but outermost electrons _______________
minimizes
electrons with parallel spins have correlated motion that ______their mutual repulsion
Paramagnetic a substance that has unpaired electrons a substance that is attracted to an external magnetic field
Diamagnetic: a substance has no magnetic moment a substance has only paired electrons a substance that is weakly repelled by an external metal field
wave (wave nature most clearly seen in diffraction)
Electrons that were thought of only as particles also have ______ nature
it is easiest to remove electrons from alkali metals
First ionization energy for Alkali metals is the lowest meaning
ionization energy is already stable- requires significant energy to remove electron
First ionization energy for noble gases is highest because
Francium is the least electronegative element (most electropositive)
Fluorine is the most electronegative element
not release energy
For noble gases, the electron affinities are greater than zero because they are already stable for a noble gas, adding an electron does ___________
transition elements valence electrons
For transition elements: we also count the outermost d electrons among the valence electrons even though they are not in the outermost principle energy level
He+ H more energy to remove the 1s electron from helium because it is attracted to the nucleus by a 2+ charge, whereas H is attracted to the nucleus by a 1+ charge. therefore the electron in helium is held more tightly (lower PE)- making it more difficult to remove and making helium atom smaller than hydrogen atom
H vs He
an interference pattern similar to that of light is observed behind the slits.. The detectors between the 2 slits detect a large number of electrons. Moving outward, the detectors alternately detect small number of electrons then small numbers again, forming interference patterns characteristic of waves
How do electrons behave if an electron beam is aimed at two closely spaced slits and detectors are set up to observe the electrons after they pass through
3,2,1 The number of electrons gained corresponds to the negative charge on the ion.
How many electrons must an atom of As, Se, and Br gain, respectively, to have a total of eight valence electrons?
1,2,3 The number of electrons lost corresponds to the positive charge on the ion.
How many electrons must an atom of K, Ca, and Ga lose, respectively, to have zero valence electrons in the n=4 shell?
metallic character
How much an element acts like a characteristic metal.
K loses its electron- leaves it with no valence electrons but an octet in the previous principal energy level Cl gains an electron and forms an octet So K+ and Cl- written as KCl
Ionic bonding : K and Cl
first: remove one core electron second: rewrite EC with the removed electron and remove more electrons (requires more energy to remove core electron than valence) third: write the EC with the two lost electrons, lose another
Ionization energy when in terms of first/second/third ionization energy
As you move to the right across a row in the periodic table, the n level stays the same. However, the nuclear charge increases and the amount of shielding stays the same because the number of inner electrons stays the same. So the effective nuclear charge experienced by the electrons in the outermost principal energy level increases, resulting in a stronger attraction between the outermost electrons and the nucleus and, therefore, smaller atomic radii..
KNOW THIS
When certain combinations form an octet or not
Lewis structure accounts for why particular combination of atoms form molecules and other do not
0
Metals lose electrons to achieve noble-gas configuration. If the valence shell is considered to be n=4, how many valence electrons are in a stable ion of a period 4 metal?
lose
Metals tend to ______ their valence electrons in a chemical change to attain noble gas configuration
g CO2 - mol CO2 - Co2 molecules
Molar Mass
systems with high PE tend to change in ways that lower their potential energy and systems with low PE tend to not change- they are stable. Because atoms with 8 electrons have particularly low PE, the noble gases are stable and they cannot lower their energy by reacting with other atoms/molecules
Noble gases?
8
Nonmetals gain electrons to achieve noble-gas configuration. How many valence electrons are in a stable nonmetal ion?
when we try to observe the hole the electron goes through (particle) we lose the interference pattern (wave) and vice versa
Observation rules?
principle level
Orbitals with the same value of n are in the same
noble gas configuration
elements without _______________ react to attend a _________-
When an atom becomes an ion, additional electrons shield the nuclear charge, whereas fewer electrons strengthen the attraction between the nucleus and the electrons. Therefore, the ionic radius is larger than the atomic radius for the same element when it becomes an anion, and the ionic radius is smaller than the atomic radius when it becomes a cation. When comparing two elements with the same electron configuration, whether an atom and an ion or two ions, the element with fewer protons will have the larger radius because it has a weaker nuclear charge.
RULE
as we move down a column in the periodic table, the principal quantum number (n) of the electrons in the outermost principal energy level increases, resulting in larger orbitals and therefore larger atomic radii as we move to the right across the4 periodic table, the effective nuclear charge experienced by the electrons in the outermost principal energy level increases, resulting in a stronger attraction between the outermost electrons in the nucleus and smaller atomic radii
SUMMARY OF TRENDS
H(wave function symbol) = E(wave function symbol H is total energy of the electron within the atom, E is energy of the electron, wave function symbol describes the wavelike nature of the electron wave function squared = orbital (probability distribution)
Schrodinger equation ( energies and orbital of electron)
the amount of energy required to remove the second electron from an already POSITIVE ion from a gaseous ion
Second ionization energy?
lattice that energy is emitted as heat when the lattice forms
Since the sodium ions are positively charged and the chlorine atoms are negatively charged, the potential energy decreases (Columbs law) when these ions come together to form_______
electronegativity difference value
Small: Nonpolar Covalent (0-0.4) Intermediate: Pure Covalent(0.4-2.0) Large: Ionic (2.0 +)
the octet rule
States that atoms lose, gain or share electrons in order to acquire a full set of eight valence electrons
Like if two Cl Atoms pair together, they get an octet. Or if two H pair together, the one unpaired electrons come together for a duet
The Lewis structure helps explain the tendency of some electrons to form diatomic molecules
No two electrons in an atom can have the same set of four quantum numbers (n, ℓ, mℓ, and ms).
The Pauli exclusion principle:
second
The _____ IE is always greater than the first IE
Energy
The __________ determines the frequency and wavelength of the photon
increase
The anions will experience a smaller effective nuclear charge, which results in an _____ in ionic radius.
Electrons are added to the lowest energy orbitals available.
The aufbau principle
Single electron traveling through space has wave nature- wavelength is related to Kinetic Energy. The faster the electron is moving, the higher the Kinetic Energy and the shorter its wavelength.
The de Broglie Wavelength
the electronegativity difference between 2 bonding atoms
The degree of polarity in a chemical bond depends on ...
psoitive
The effective nuclear charge experienced by an atom's outermost electrons continues to become more________ as we move to the right across across the rest of the second row, resulting in successively smaller atomic radii. The same trend is observed for most main group elements
(Delta)E= -2.18 x 10^-18J(1/n^2-1f/n^2i)
The equation for the change in energy that occurs in an atom when an electron changes energy levels
heat (the process is exothermic)
The formation of an ionic compound from its constituent elements usually gives off quite a bit of energy as ________
smallest whole number ratio of ions
The formula of an ionic compound reflects the __________
Emmited light
The greater the difference between the principal quantum numbers (n) involved in the electron transition (to the same ground state), the greater the frequency of the ______
the attraction between two covalently bonded atoms is due to sharing one or more electron pairs in the space between them- thus each bond links just one specific pair of atoms in contrast to ionic bonds which are nondirectional and hold together an entire array of ions- thus the fundamental units of molecules can react with each other in many different ways
The lewis structure also accounts for why covalent bonds are highly directional
Energy
The more we know about position, the less we know about ______. And vice versa (complementary properties)
maximum number
The number of columns in a block corresponds to the _______ maximum number of electrons that can occupy a particular sublevel of that block
smaller
The smaller the magnitude of the charge separation, and the smaller the distance between charges, the _______ the dipole moment
1+
The valence electron in lithium experiences the 3+ charge of the nucleus through the shield of the 2- charge of the core electrons. The effective nuclear charge acting on the valence electron is approx _______
1 find atomic number to figure out number of electrons 2 distribute electrons 3 S: ONE P: THREE D: FIVE F: SEVEN
To write an electron configuration
higher in frequency and therefore shorter in wavelength than transitions between orbitals that are closer in energy
Transitions between orbitals that are further apart in energy produce light that is __________________
except for helium, the number of valence electrons for any main group element is equal to its lettered group number ( row number of MGE is equal to n number)
Valence electron row rule
the valence electrons are those in the outermost principal energy level (highest n)
Valence electrons for main group elements
Complimentary properties: the more we know about one the less we know about the other- in quantum mechanics the observation of an event effects the outcome
Wave and Particle nature are...
To melt the solid, forces must be overcome, which requiresa significant amount of heat model counts for in conductivity- does not account for electricity except for predicting the conduct electricity
We model an ionic solid as lattice of individual ions held by forces that are not directional (as we move away from the center of the ion, the forces are equally strong in all directions) what does this say about melting?
the name of the polyatomic ion whenever it occurs
We name ionic compounds in the same way we name other ionic compounds except we incorporate _______
The wave nature of the electron is an inherent property of individual electrons. In this case, the unobserved electron goes through both slits- it exists in two states simultaneously- and interferes with itself. EXPLAINS EXISTENCE OF STATIONARY STATES and prevents electtons from crashing into nucleus
What can be concluded from the fact that: electrons come out of the source singly and we can record where each electron stikes the detector after it has passed the slits. We record the position of thousands of individual electrons and fine the same interference pattern
The particular orbitals that electrons occupy for that atom
What does an electron configuration show?
an electron particle traveling through a single slit with no interference pattern (observing factors forces an electron into one state and only can go through one slit)
What does an experiment designed to observe the electron traveling through the slits?
the orientation of the orbital -1 to 1. ( if l=3, ml values could be -3,-2,-1,0,1,2,3)
What does ml determine?
elements with three of fewer valence electrons
What elements are more likely to lose electrons
The light flashes near the slit the electron comes out of and the interference pattern goes away- WE CAN NEVER SEE BOTH SEE THE INTERFERENCE PATTERN AND simultaneously DETERMINE WHICH HOLE ELECTRON GOES THROUGH
What happens when a laser beam is placed directly behind the slits?
potential energy (E) of 2 charged particles depends on their charges (q1 and q2) and on their separation (r) like charges attract, opposite charges repel
What is Colombs law
when filling degenerate orbitals electrons fill them singly first: reflects atoms tendency to find the lowest energy state possible
What is Hund's rule
Linus Pauling, The Nature of the Chemical Bond
electronegativity was quantified by American chemist
alkali: 1+ alkaline: 2+ halogens: 1-
alkali, alkaline, halogens trend?
gain
all nonmetals tend to ______ electrons when they undergo chemical changes to attain noble gas configurations
first
always need more energy to remove the second electron rather than the ____ because we remove electrons ,the resulting ion becomes more positive, so it requires more energy to remove a negative electron from an increasingly positive ion
paramagnetic
an atom or an ion that contains unpaired electrons is attracted to an external magnetic field , and we say that atom is ______
diamagnetic
an atom or an ion which all electrons are paired is not attracted to an external magnetic field- it is instead slightly repelled- and we say it is ______
valence electrons
an atom's _______________- are the most important in chemical bonding
THE COMPLEMENTARITY OF THE WAVE NATURE AND PARTICLE NATURE OF THE ELECTRON RESULTS IN THE COMPLEMENTARITY OF VELOCITY AND POSITION
an electron is observed as wither a wave or a particle never both- explain
anions: _____ the number of electrons indicated by the magnitude of the charge of the anion (-charge) cations:______ the number of electrons indicated by the magnitude of the charge transition metal cation: we remove the electrons in the highest n value orbitals first
anions, cations, transition metal cations?
no- in quantum mechanics trajectories are replaced with probability distribution maps
are electrons deterministic (present determines the future)
helps explain the transition metal cation trend
as discussed previously, the ns and (n-1)d orbitals are extremely close in energy and depending on the exact configuration, can vary in relative energy ordering as the (n-1)d orbitals begin to fill in the first transition series, the increasing nuclear charge stabilizes the (n-1)d orbitals relative to the ns orbitals. This happens because the (n-1)d orbitals are not the outermost (or highest n) orbitals and are therefore not effectively shielded from the increasing nuclear charge by the ns orbitals
Zeff decreases and the ionic radius becomes larger.
as more electrons are added, what happens to Zeff?
Zeff increases and the ionic radius becomes smaller
as more electrons are removed, what happens to Zeff?
decreases
as you move away from the nucleus (center of plot), the probability density _______
1. as we move down a column (or family) in the periodic table, the atomic radius increases 2. as we move to the right across a period (or row) in the periodic table, the atomic radius decreases
atomic radii trends
a set of average bonding radii determined from measurements on a large number of elements and compounds it represents the radius of an atom when it is bonded to another atom and is always smaller than the VanderWalts radius
atomic radius
most atoms contain many electrons occupying a number of different orbitals (all orbitals in ballon(atom))
atoms are usually drawn in spheres because________
valence
electrons farthest from the nucleus
because electrons occupy the lowest energy orbitals available when the electrons are at ground state, only 2 electrons w opposite signs are allowed in each orbital
aufbau principle - this pattern of orbital filling
decreases Li much bigger than Li+ CATIONS ARE MUCH SMALLER THAN THEIR CORRESPONDING NEUTRAL ATOMS
because the outermost electron is shielding by the core electrons, it makes up a lot of the size of the atom, so when an anion loses this electron ,the size majorly _______
nonmetals: one half the distance between two of the atoms bonded together metals: one half the distance between two of the atoms next to each other in a crystal of the metal
bonding atomic radius (covalent radius)
- explain how atoms bond together to form molecules - exbalins why some atoms are stable and others are not - predict shapes of molecules
bonding theories?
we can get a sense of the degree to which the electron is transferred (or the degree to which the bond is ionic)
by comparing the actual dipole moment of a bond to what the dipole moment would be if the electron were completely transferred from one atom to another...
the force that hold atoms together in a compound result of interactions between charged particles (electrons and protons)
chemical bond?
they lower the potential energy between the charged particles that compose atoms
chemical bonds form because
- the quickest and easiest way to represent a compound - indicates the elements present in the compound and the relative number of atoms/ions in each
chemical formula?
first
chemical formulas usually list the more metallic (positively charged) elements _______
the unknown compound undergoes combustion (or burning) in the presence of pure oxygen
combustion analysis (way to obtain empirical formulas)
binary compounds
contain only two different elements.
molecules, molecular compounds
covalently bonded atoms form ______, and the resulting compounds are called ________
change in energy
delta E = Efinal-Einitial
the same
each subsequent row, the highest principal quantum number increases by one as we move down the column, the number of electrons in the outermost principal energy level (highest n value) remains ______
actual nuclear charge (Z) minus the charge shielded by other electrons (S)
effective nuclear charge
negative/exothermic because energy is generally released when an electrons is added the attraction between the nucleus of an atom and the incoming electron usually results in the release of energy as the electron is gained
electron affinity is generally ______
one electron does not have more or less spin than the other spin up: 1/2 spin down: -1/2
electron spin (ms)?
the ability of an atom to attract electrons to itself in a chemical bond (which results in polar and ionic bonds) in HF, we would say fluorine is more electronegative than hydrogen because it takes a greater share of the electron density in HF
electronegativity
the larger the atom, the less ability it has to attract electrons in a chemical bond
electronegativity is inversely related to atomic size...
decreases
first ionization energy generally _______as we move down a column (or family) in the periodic table because electrons in the outermost principal level are increasingly farther away from the positively charged nucleus and therefore held less tightly
increases
first ionization energy generally _____as we move to the right across a row in the periodic table because the electrons in the outermost principal energy level generally experience a greater effective nuclear charge. this means electrons feel a higher and higher positive charge , attracting more to the nucleus as we go right. Meaning it requires more energy to sperate the negative and positive charges.
the outermost principle energy level (highest n value)
for MAIN GROUP electrons: the valence electrons are those inb ______
electrons in the outermost principal level are farther away from the positively charged nucleus- and are therefore held less tightly- as we move down the column...THIS RESULTS IN LOWER IONIZATION ENERGIES AS WE MOVE DOWN THE COLUMN
for a given sublevel, orbitals with higher principal quantum number is bigger than orbitals with smaller principal quantum number (4s larger than 3s), which means....
larger o2- much bigger than o
for an anion, there is one additional outermost electron but no additional proton to increase the nuclear charge, so the extra electron increases the repulsion among the outermost electron making the anions much ________ than their corresponding neutral atoms
less
for group 1A metals, electron affinity becomes _______ exothermic as we move down the row
2 vowels
for molecular compounds, if a prefix ends in a or o, drop it to avoid ________
minus 2
for the f block, the principal quantum number of the f orbitals fill across each row number _______
(number of atoms in 1st element in chemical formula x atomic mass of 1st element) + (number of atoms of 2nd element in chemical formula x atomic mass of 2nd element)
formula mass =
alkali metals ns^1 one electron beyond a noble gas, so they often lose the ns^1 electron to form an ion with 1+ charge in their reactions
group 1A elements?
alkaline earth metals ns^2 tend to lose ns^2 electron to form a 2+ charge in their reactions
group 2A elements?
halogens ns^2Np^5 one electron short of noble gas, to to gain electron in reactions with metal to form ions with 1- charge
group 7A elements?
the number of sublevels in any level is equal to n, so n=1 is 1 sublevel, n=2 is 2 sublevel
how are sublevels and n related
name of cation (metal) + charge of cation (metal) in roman numerals + ide
how do you name a binary ionic compound containing a metal that forms more than one type of cation
name of the cation (metal) + base name of the anion (nonmetal) + ide
how do you name a binary ionic compound containing a metal that forms only one type of cation
prefix-name of 1st element-prefix-base name of 2nd element plus ide the first element is more metal-like (the one more towards the left and bottom of the PT) generally we write the name of the element with the smallest group number first (if they lie in the same group, we write the element with the greatest row number 1st)
how to name molecular compounds
contain a specific number of water molecules associated with each formula unit hemi: 1/2-octa 8
hydrates - H2O
effective nuclear charge
if one electron comes toward the lithium ion: (3+ from the nuclus and 2- from the electrons for a net charge of +1)
core
if were removing one core and one electron, it should require more energy to remove a _____ electron
equal
in a chemical formula, the sum of the charges of the anions must be __________ to the sum of the charges of the cations
elements combine in fixed, definite proportions whereas a in a mixture, elements can mix in any proportion
in a compound,
dipole moment
in a covalent bond: electrons are shared between atoms in a polar covalent bond: electrons are shared unequally- electrons spend more time near one atom then the other (creates _______)
dots surrounding the abbreviation of the element
in a lewis structure we represent the valenc electrons of main group elements as _______
single location- always moving
in an orbital, the electron does not have a _____
the same combination of elements may form several different molecular compounds each with a different formula
in contrast to an ionic compound, the formula for a molecular compound cannot always be determined from its constituent elements because ...
between every two atoms the place to terminal, then to central giving octet (duets for H) if any atoms lack an octet, form double or triple bonds from lone pairs on terminal atoms
in lewis structures, where do electrons go first
small is a covalent bond ELECTRONS TRANSFERRED
intermediate electronegativity difference (like 2 nonmetals): polar covalent bond (partial negative on the more electronegative atom and a partial positive on the less electronegative atom) ELECTRONS SHARED UNEQUALLY
1. metal forms only one type of ion (always same charge)- main group metals 2. metal forms more than one type of ion (charge can differ)- transition metals usually
ionic compound: metal and non mental 2 sections?
positive and negative ion
ionic compounds always contain___________
charge neutral
ionic compounds must be
positive
ionization energy is always ________ because removing an electron always takes energy
the amount of energy required to remove an electron for a gaseous electron or ion (they are endothermic because it requires energy ti remove an electron)
ionization energy?
more
it requires significantly _____ energy to remove a core electron than a valence electron
The successive ionization energies for valence electrons in an atom are increasing but not dramatic. Once those valence electrons are removed, the next electron removed is from a previously filled inner shell. This ionization is much more difficult, energetically, and this is where the "jump" occurs. Since Li has one valence electron, the "jump" will occur between the 1st and 2nd ionization energies. N has five valence electrons and the "jump" will occur between the 5th and 6th ionization energies. Be has two valence electrons and the "jump" will occur between the 2nd and 3rd ionization energies. S has six valence electrons and the "jump" will occur between the 6th and 7th ionization energies.
jumps with valence electrons?
ionic ELECTRONS SHARED EQUALLY
large electronegativity difference between two atoms (like metals and nonmetals), the electron from the metal is almost completely transferred to the nonmetal, and the bond is _______
de Broglie reaction
mass times velocity is momentum- electron inversely proportional to momentum VELOCITY IS RELATED TO WAVELENGTH
lose electrons gain electrons so, when a metal interacts with a nonmetal, it can transfer one or more of its electrons to the nonmetal. the metal then becomes a CATION (positively charged atom) and the non metal becomes a ANION (negatively charged atom)
metals have a tendency to: nonmetals have a tendency to:
lose
metals tend to ______ electrons when they undergo chemical changes
two or more nonmetals
molecular compounds are....
within, between molecular compounds tend to have a lower melting and boiling point than ionic compunds
molecular compounds have strong covalent bonds _______ molecules and weak intermolecular forces _______ molecules
n = molecular mass / empirical formula mass
molecular formula = empirical formula x n where n=1,2,3 molar mass = empirical formula molar mass x n
formula mass
molecular mass and molecular weight are the same as
molecular model
more accurate and complete way to specify a compound atoms as balls and chemical bonds as sticks
polar
more electronegative, more ______
OCTET
most stable compound
En=-2.18 x 10^-18J(1/n^2) The energy is negative because the electron's energy is lowered by its interaction with the nucleus The orbitals- as n increases, energy increases (less negative) as n increases, the spacing between the energy levels become smaller
n energy?
ionization energies (their electrons are relatively difficult to remove) So, when a nonmetal bonds with another nonmetal, neither atom transfers electron to the other. Instead, the two atoms share electrons. The shared electrons interact with the nuclei of the bonding atoms, lowering the PE.
nonmetals tend to have a higher _____________
constant
number of electrons in outermost level remains
mass percent composition
one way to express how much of an element is in a given compound is to use the elements ____________
chemical bonds
only noble gases contain full outer principal quantum levels. because the rest of these elements do not posses the stability of the noble gases, they form ______ to become more stable. (to lower the PE of the charges particles)
sublevel
orbitals with the same value of n and l are in the same An atomic orbital, or collection of atomic orbitals, that occupy a principal energy level and are called s, p, d, and f.
ic represents greater charge (III)
ous indicates lesser charge (II)
electrons beyond the noble gas configuration that precedes the noble gas
outer electron configuration: inner electron configuration:
ClO - HYPOchlorITE ClO2- chlorITE ClO3- chlorATE ClO 4- PERchlorATE
oxyanion naming?
Anions containing oxygen and another element (most common polyatomic ion)
oxyanions
octet
particularly stable because they have a full outer principal level- easily identified because they have 8 dots
As the outer electron undergoes penetration into the region occupied by the inner electrons, it experiences a greater nuclear charge and therefore (coulombs law- lower energy (bc negative electron to positive nucleus)
penetration rule
the ratio of a bond's actual dipole moment to the dipole moment it would have if the electron were completely transferred from one atom to the other, multiplied by 100 percent
percent ionic character
having a positive pole and a negative pole
polar
an ion composed of 2 or more atoms
polyatomic ions
polar covalent
pure covalent and ionic are two extremes-- most covalent bonds between dissimilar atoms are actually ________, somewhere between the two extremes
represents the total probability of of finding the electron within a thin spherical shell at a distance r from the nucleus - not probability density at point r, but total probability at a radius r - probability has maximum at nucleus, where RDF has zero at nucleus
radial distribution function
S: 1 p: 2 d: 4 f: 8
shapes pf orbitals:
a fraction ...x/100 or 100/x you can use this as a conversion factor
since percent means per hundered, we can also write mass percent composition as:
shared electrons in a covalent chemical bond hold the bonding atoms together by attracting the positive charges of their nuclei
stability of covalent bonds:
properties
structure determines ______
1. lower energy orbitals fill before higher energy orbitals: 1s 2s 2p 3p 4s 3d 4p 5s 4d 5p 6s 2 orbitals can hold no more than 2 electrons each- spin is opposite in same orbital- another way of expressing Pauli exclusion principle 3 when orbitals of identical energy are available, electrons first occupy the orbital singly with parallel spins rather than in pairs (hunds Rule)
summarize orbital filling
roughly constant
the atomic radii of the transition elements _____ follow the same trend as the main group elements as we move to the right across the row instead of decreasing in size, the radii of the transition elements stay ________ across each row
formula mass
the average mass of a molecule (or formula unit) of a compound is a ___________
formula unit or the smallest, electrically neutral collection of ions exists as a larger lattice
the basic unit of an ionic compound is the __________
An ionic bond
the bond that forms between a metal and a nonmetal is _________
covalent bond
the bond that forms between two nonmetals is a _____
lattice energy
the energy associated with the formation of a cystaline lattice of alternating cations and anios from the gaseous ions.
Delta E atom = -E photon
the energy carries a negative sign because the atom emits energy as it relaxes from n=3 to n=2
electron affinity
the energy change associated with the gaining of an electron by the atom in the gaseous state. Electron affinity, EA, is the energy required to add an electron to a neutral gaseous atom and is related to an element's position on the periodic table.
ionization energy (IE)
the energy required to remove an electron from the atom or ion in the gaseous state
second ionization energy, third ionization energy notice that the second ionization energy is not the energy required to remove 2 electrons from Na, but rather the energy required to remove 1 electron from Na+
the energy required to remove the second electron, the third electron
smaller bc 16+ pulling on 18 electrons is a bigger atomic radius than 20+ pulling on 18 electrons
the greater the nuclear charge in atoms or ions withthe same number of electrons, the _______ the atom
outermost electrons
the key connection between the macroscopic world (elements chemical properties) and the particulate world (atom's electronic structures) lies in the __________
valence electrons are dots lewis structures are molecules GOOD FOR MAKING PREDICTIONS ABOUT MOST MOLECULES
the lewis model
chemical bonding involves the transfer of sharing valence electrons between 2 or more atoms
the lewis model focuses on valence electrons because...
upside down u = qr
the magnitude of a dipole moment created by separating two particles of equal but opposite charge of magnitude q by a distance r is given by the equation
that element's percentage of the compound's total mass
the mass percent composition or mass percent of an element is...
the mass in grams of 1 mol of its molecules or formula units--is numerically equivalent to its formula mass formula mass:amu molar mass:g/mol
the molar mass of a compound
noble gases (8A)
the most unreactive elements in the entire periodic table
columns
the number of ______ in a block corresponds to the maximum number of electrons that can occupy the particular sublevel of that block
n^2 so n=3 level has 9 orbitals
the number of orbitals in any level is equal to what
2l + 1 p sublevel l=1, has 3 orbitals
the number of orbitals in any sublevel is equal to what
no bond is 100 percent ionic. in general, bonds with greater than 50 percent ionic characters are referred to as ionic bonds
the percent ionic character generally increases as the electronegativity difference increases, however we can see....
the row number minus one
the principal quantum number of the d orbitals that fill across each row in the transition series is equal to ______
the highest n
the row number of the main group elements is equal to________
covalent bonds
the shared electrons are chemical _______
phase
the sign of the amplitude of a wave is known as the ______
attract one another and form an ionic compound, which in the solid state is composed of a lattice (a regular three dimensional array of alternating cation and anions)
these oppositely charged ions...
three shared electron pairs very strong- hard to break- un reactive molecule explains why Nitrogen is a diatomic molecule
triple bonds
we cannot simultaneously measure an electrons position and wavelength with infinite precision (more accurately you know the position less accurately you know the velocity- Heisenberg's uncertainty principle)-
velocity: related to wave nature position: related to particle nature- particles have well defined positions and waves do not what does this mean?
the probability of finding that electron in space (probability over unit volume)
wave function squared is the probability density which is...
relative number of atoms of each element in a compound actual number of atoms of each element uses lines to represent covalent bonds and shows how atoms in a molecule are connected or bonded to each other empirical formula for hydrogen peroxide: HO LEAST INFO molecular formula: H2O2 structural formula: H-O-O-H MOST INFO
we categorize chemical formulas into 3 different types empirical formulat: molecular formula: structural formula:
dash
we often represent a bonding pair of electrons by a ____ to emphasize the pair constitutes a chemical bond
a dipole moment (upside down u) occurs anytime there is a speration of positive and negative charge
we quantify the polarity of a bond bu the size of its dipole moment
transition level ions
we remove the ns electrons before the (n-1)d electrons when writing configurations for ________
in complete principal energy levels and those in complete d and f sublevels
what are core electrons
s and p blocks
what are the main group elements
1. Potential energy (E) associated with the interaction of like charge is positive but decreases at particles get farther apart. Since systems tend toward lower PR, like charges that are close together have high PE but tend to move away from one another to lower PE LIKE CHARGES REPEL 2. The potential energy (E) associated with the interaction of unlike charges is negative and becomes more negative as particles get closer together. Since systems tend toward lower PE, the interaction of unlike charges draws them closer together (toward lower PE) UNLIKE CHARGES ATTRACT ONE ANOTHER 3. The magnitude of the interaction between charged particles increases as the charges of the particle increase. (an electron eith a charge of 1- is more strongly attached to a nucleus of 2+ rather than 1+)
what are the three important conclusions from colombs law
d and f blocks
what are the transition elements
sublevel energy splitting
what determines the order of orbital filling within a level
The shape of the orbital - can be 0 to (n-1)
what does l determine?
the orientation of the spin of the electron.
what does ms determine?
the overall size and energy of an orbital
what does n determine?
the total probability of finding the electron within the spherical shell at a disance r from the nucleus
what does the radial distribution function for an atomic orbital show
for multi electron atoms, any single electron experiences both positive charge of nucleus (attractive) and negative charges of other electrons (repulsive). Repulison of one electron by other electrons is screening or shielding that electron from the full effecgts of nuclear charge
what is shielding
spacial distributions pf electrons within a sublevel
what is the energy splitting a result of
the result of multiplying 1. the probability density function(wave function squared) (probability divided by unit volume). The PDF has a maximum at the nucleus and decreases with increasing r 2. the volume of the thin shell ( 0 at the nucleus, increases with r increasing)
what is the shape of the radial distribution
inward pull of the nucleus on the electrons in the outermost principal energy level (highest n)
what is the trend in the atomic radius based on
as we move down a column, n of the valence electrons increases and the valence electrons occupy larger orbitals
what results in larger atoms (atomic radii trends)
particularly low
when a quantum level is completely full, the overall potential energy of the electrons that occupy that level is ______
excited or promoted to a higher energy orbital. However this makes the atom unstable, and it quickly flies back or relaxes to a lower energy level (as it does it releases a photon of light containing an amount of energy equal to the energy difference of the two energy levels)
when an atom absorbs energy, an electron in a lower energy orbital is ________-
low
when an outer principal quantum level is particularly low, the overall potential energy of electrons that occupy that level is particularly ____
removal
when there is a big jump in ionization energy, this means _______ of an electron There is generally a large jump in ionization energy (IE) between the valence electrons of an element and its core electrons.
if these interactions lead to an overall net reduction of potential energy between charged particles, a chemical bond forms covalent vs ionic depending on the atoms
when two atoms face each other: - electrons go towards nucleus - electrons repel electrons - nucleus repels nucleus
