Chapter 9 Periodic Properties of the Elements Flashcards
Necessary for the rapid electrical signaling in these cells
ion channels
Establish and control a voltage gradient in neurons
ion channels
properties whose values can be predicted based on the element’s position on the periodic table.
periodic properties
what is medeleev known for?
look at notes
when the elements are
arranged in order of increasing atomic
mass, certain sets of properties recur
periodically.
periodic law
allows us to predict
the properties of an element based on its
position on the table.
Mendeleev’s Periodic Law
what doesn’t Mendeleev’s Periodic Law explain?
why the pattern exists.
is a theory that explains
why the periodic trends in the properties exist.
Quantum mechanics
the location of electrons in atoms
electron configurations.
A description of the orbitals occupied by electrons is called
an
electron configuration.
which gives similar information but symbolizes the electron as an arrow and the orbital as a box.
Orbital Diagrams
Spinning charged particles generates a what?
magnetic field.
is a fundamental property of all electrons.
Spin
The electron’s spin adds a fourth quantum
number to the description of electrons in an atom, called the
spin quantum number, m(s)
what values does m(s)
can have values of +½ or −½.
what is pauli exclusion principle
*No two electrons in an atom may have the same set of
four quantum numbers.
*Therefore, no orbital may have more than two electrons,
and they must have opposite spins.
how many electrons are in an orbital
2
how may electrons can s sublevel have?
2
how may electrons can p sublevel have?
6
how may electrons can d sublevel have?
10
how may electrons can f sublevel have?
14
Electron-Electron interactions lead to:
–Shielding
–Penetration
describes the attractions
and repulsions between charged particles.
Coulomb’s law
what is important about Coulomb’s law
on notes
These repulsions cause the electron to have
a net reduced attraction to the nucleus;
shielding
The total amount of attraction that an
electron feels for the nucleus is called the
effective nuclear charge
The what an electron is to the nucleus,
the more attraction it experiences.
closer
The better an outer electron is at what
through the electron cloud of
inner electrons, the more attraction it will
have for the nucleus.
penetrating
related to the orbital’s radial distribution
function.
degree of penetration
Penetration and shielding cause the energies of sublevels in the same principal level to what?
not be degenerate
where are the effects of penatration important
in the forth and fifth prinicple levels
The energy separations between one set of orbitals
and the next become smaller beyond the
4s
For multi-electron atoms, the energies of the
sublevels are
split not degenerate
why are multi-electron atoms, the energies of the
sublevels split?
shielding and penetration
what do orbitals in sublevels do?
degenerate
energy levels and sublevels fill from what to what
low to high
energy levels and sublevels fill from lowest energy to
high:
energy levels and sublevels fill from lowest energy to
high:
no more than two electrons per orbital.
Pauli exclusion principle
When filling degenerate orbitals, place one electron in
each orbital before completing electron pairs.
Hund’s Rule
listing of the
sublevels in order of filling with the number of
electrons in that sublevel written as a
superscript.
The electron configuration
Electrons in all the sublevels with the
highest principal energy shell are called the
valence electrons
electrons in lower energy shells are called
core electrons
One of the most important factors in the
way an atom behaves, both chemically and
physically, is the what?
number of valence electrons.
corresponds to the number of valence electrons.
group number (main group elements)
corresponds to the principal
energy level of the valence electrons.
period number
is the maximum
number of electrons the sublevel can hold.
length of each “block”
slide 55-65
explains this because
the number of valence
electrons and the types of
orbitals they occupy are
also periodic.
quantum mechanical model
eight valence electrons.
noble gases
which noble has only two valence
helium
nonreactive.
noble gases
practically inert
He and Ne
The reason the noble gases are so
nonreactive is that the
electron
configuration of the noble gases is
especially stable.
have one more electron
than the previous noble gas.
alkali metals
tend to lose one electron,
alkali metal
Forming a cation with a 1+ charge
alkali metal
one fewer electron than the next
noble gas
halogens (7A)
forming an anion with charge 1−.
halogens
In their reactions with nonmetals, they tend
to share electrons with the other
nonmetal so that each attains the electron
configuration of a noble gas.
halogen
what eclectron configurations with result from ions
the same as the
nearest noble gas.
are formed when nonmetal atoms gain
enough electrons to have eight valence electrons
anions
are formed when a metal atom loses all its
valence electrons, resulting in a new lower energy level
valence shell.
cations
Electron configurations that result in unpaired
electrons mean that the atom or ion will have a
net magnetic field;
paramagnetism.
Electron configurations that result in all paired
electrons mean that the atom or ion will have no
magnetic field; this is called
diamagnestism
measuring the radius of nonbonding pairs
Van der Waals Radius
measuring the radius of bonding pairs
Covalent Radius
is an average radius of an atom based on
measuring large numbers of elements and compounds.
Atomic Radius
is the trend for atomic radius?
Atomic radius decreases across period (L to R)
Atomic radius increases down group
is a net positive charge that is attracting a particular electron.
effective nuclear charge
is the nuclear charge (i.e. atomic number),
Z
is the number of electrons in lower energy
levels.
S
what is the size of an atom is related to what?
the distance the valence electrons are from the nucleus.
The larger the principal
energy level of an orbital, the
larger its what?
volume
predicts the atoms should
get larger down a column.
Quantum-mechanics
The larger the effective nuclear charge
an electron experiences, the what?
the stronger the attraction it will have for the
nucleus.
The stronger the attraction the valence
electrons have for the nucleus, the what?
closer their average distance will be to
the nucleus.
predicts the atoms should get smaller across a
period.
Quantum-mechanics
Atomic radii of transition
metals are what?
roughly the same
size across the dblock.
the ionic radii trends, what are the sizes of the ions and exceptions
anions > neutral > cations
Except Rb+ and Cs+ bigger or same size as F− and O2− .
the larger positive charge the what?
smaller cation for isoelectronic species
same electron configuration
isoelectronic
The larger the negative charge what?
the larger the anion for isoelectronic species
When atoms form cations, the valence
electrons are what?
removed
These “new valence electrons” of a cation also experience what?
a larger effective nuclear charge
When atoms form anions, electrons are what?
added to the valence shell
These “new valence electrons” of a anion also experience what?
a smaller effective nuclear charge
Minimum energy needed
to remove an electron from an atom or ion in
the gas phase
Ionization Energy
energy to remove the first electron from
the neutral atom
First IE
energy to remove an electron from the
1+ ion
Second IE
what is the trend for atomic radius
down column increases
across period decreases
what is the trend for ionic radius
down column increases
across period decreases
what is the trend for first ionization energy
down column decreases
across period increases
predicts the atom’s first ionization energy should get larger across a period and decrease down the group
Quantum-mechanics
Atomic size decreases due
to what?
having more protons
than electrons
when core electrons are
removed what happens?
here’s a large increase in
energy
what kind of process is ionization energy?
endothermic
Energy released when a
neutral atom gains an electron in the gas phase.
electron affinity
is defined as exothermic
(−H), but can be endothermic (+H).
electron affinity
the more negative the number the what the EA?
the larger
is how closely an element’s
properties match the ideal properties of a metal.
metallic character
what is the trend for metallic character
down column increases
across period decreases
predicts that metallic character should increase down a column because the valence electrons are not held as strongly.
Quantum-mechanics
predicts that metallic character should
decrease across a period because the valence electrons are held more strongly and the electron affinity increases.
Quantum-mechanics
