welcome to successive ionization energies and their patterns many elements need to
lose electrons to become stable but electrons are held to the atom by the attractive force
of the nucleus positive and negative charges attract each other so energy is required to
remove an electron from that attractive force that energy is called ionization energy or ie because
removing an electron creates a charged atom which is called an ion the unit for ionization
energy is kilojoules per mole which refers to the amount of energy required to remove one
mole of electrons from one mole of atoms given this definition does the unit kilojoules per
mole make sense let's begin by taking a look at energies required to remove electrons from
magnesium the electron configuration is shown at top right and we are keeping track of the
ionization energy in the graph at bottom right and we see that neutral magnesium has 12 protons
and 12 electrons note that magnesium wants to lose its two valence electrons to acquire
the stable electron configuration of neon the first ionization energy is relatively low as
shown on the graph now however with one less electron there is more attractive force per
electron from the same 12 protons how will that change the amount of energy needed to remove the
second electron got it yes you're right it is harder to remove the second electron it
requires more energy notice that magnesium is now a 2 plus ion and has reached a stable neon
configuration with even more attractive force per electron but other relevant changes have
occurred as well shielding is greatly reduced from 10 to 2 so effective nuclear attraction
or Zeff significantly increases the attractive force on the current outer electrons and it has
reached a stable noble gas configuration what will all of that do to the amount of
energy required to remove the third electron got it yes that's right it takes a lot more
energy these are called successive ionization energies the first ionization energy or first
OEE is the energy required to remove the first electron the second ie is the energy required
to remove this second electron and so on so these are successive ionization energies or
successive ii's what patterns can we see when looking at successive ionization energies and
adjacent elements let's compare the success of I ease of sodium magnesium aluminum and silicon
first and very importantly we need to make sure we are acquainted with where valence and core
electrons are on our atomic model it is the outer energy level where the valence electrons are and
it is the inner energy levels where the core or inner electrons are note that with these four
elements the core electrons represent the stable noble gas configuration of neon also important
notice that each succeeding element has one more proton which increases the attraction the nucleus
has four their electrons and now we can compare their successive ionization energies let's keep
track of each successive ionization energy on a vertical axis at left the first ionization energy
of sodium is low but that gets us to a neon configuration so will there be a large change
with the second ie yes sodium second ionization energy is nearly ten times that of its first OEE
how does that compare with magnesium we know the first and second ionization energies are
low but the third now removing an electron from a neon configuration is much higher can you see
what the pattern will be with aluminum and silicon what will happen to their ionization
energies once they have lost enough electrons to get to a noble gas electron configuration
for aluminum the first second and third II's are relatively low those three ionization energies
have removed all the valence electrons the fourth ie removes an electron from the core electrons a
neon configuration requiring a big jump in energy for silicon we see a similar pattern now removing
the fourth valence electron gets us to a neon configuration what's going to happen with the
fifth ionization energy you're right a big jump for the fifth ionization energy which takes from
a noble gas electron configuration if we compare the successive ionization energies in a table
with ionization energies four valence electrons in yellow and core ionization energies in orange we
can see the big jumps and ionization energies for each element occurs at the point when removing an
electron from a noble gas electron configuration sodium loses one valence electron to get to the
ten electrons of the neon configuration so there is a big jump at the second ie magnesium loses
two electrons to become stable so the big jump is at the third ie aluminum loses three electrons to
have an en configuration and so the big jump is at the fourth ie and silicon loses four electrons
to get to the core and so it's big jump is at the fifth ionization energy what do you think
the pattern would be for elements and other periods notice that the amount of electrons
removed before a large change in ionization energy is simply equal to the number of valence electrons
for that element and so identifies the group of that element elements with one electron removed
before a large ionization energy change all have one valence electron and so are in Group
one elements with two electrons removed before a large ionization energy change I'll have two
valence electrons and so on you should be able to determine where the large ion is a
energy change will occur for any element in groups 1 2 and 13 through 18 based on
their number of valence electrons note that we have only dealt with ionization energies
of main group or representative elements because transition metals are filling D
orbitals and can lose more than one specific amount of electrons to become stable their
successive ie patterns are more obscure that's it for today's mad scientist production see ya