ionization energy Flashcards
what is ionization energy?
the amount of energy required to remove an electron from atoms in 1 mol of gaseous atoms to form 1 mol of gaseous ions
from where do electrons start being removed?
from the outer shell to inner one
what are 4 factors which effect the first ionization energy
1- distance of electrons from nucleus
2- nuclear charge
3- shielding effect
4- spin-pair repulsion
how does the distance of electrons from the nucleus effect the ionization energy?
the greater the distance of electrons and nucleus, the lower the ionization energy. The attractive forces of electron and nucleus decrease causing less energy required to overcome their attractive forces hence a lower ionization energy
how nuclear charge effect the ionization energy?
the greater the nuclear charge, the greater the ionization energy. As the nuclear charge increases, there is more attractive forces which need a lot of energy to overcome hence a greater ionization energy
how shielding effect the ionization energy?
the greater the shielding effect, the lower the ionization energy. In the shielding effect, the inner electrons repel the outer electrons allowing the outer electron to be removed easily
how spin-pair repulsion effect the ionization energy?
in an atomic orbital, with 2 pairs of electrons repel, lower energy is required to remove the electron hence the lower ionization energy. in a atomic orbital of 1 electron, the ionization energy is greater due to no repulsions
write an equation using the symbol X for the first ionization energy
X= X+ * e
*- represent addition
write an equation for using CL for the 4th ionization energy
CL3+= CL4+ * e-
tip= the ionization energy value is the charge of the
product.
explain how ionization energy changes across the period
across the period,
a) the proton number increases causing a
greater effective nuclear charge.
b) An increases in the effective nuclear charge
decreases the atomic radius due to the
attractive forces of electrons towards the
nucleus leading to greater ionization energy
to overcome this attractive force.
explain how ionization energy changes down the group
down the group,
a) there is an increases in atomic radius due to the
addition of electron shells. This increases the
distance between the electron and nucleus and
leading to lower attractive forces ,hence a lower
ionization energy.
b) The also a shielding effect also increases in which
the outer electrons repel leading to lower ionization
energy
general ways to read ionization energy graphs
1- when there is a big jump, a new shell closer to the nucleus (inner shell) is found
* each big jump indicates being in a new inner shell
2-subshells in the same shell will have similar trends
*e.g.; 2s2, 2p6 will have similar trends
3- the number of electrons before the 1st big jump indicates number of outer electrons
