Atomic Structure- Ionisation energy and periodicity COPY Flashcards
What is the definition for first ionisation energy?
Ionisation energy is the amount of energy needed to remove a mole of electrons from a mole of atoms, in the gaseous state.
When an atom is ionised where is the first electron removed from?
The outer most shell
What is the unit for ionisation energy?
kJmol-1
What do the periods tell you about an atom and how does in change down a group?
Periods tell you the number of shells; increasing down a group.
The number of shells increases down the group. How does this affect shielding?
Shielding increases
How does the number of shells affect electrostatic attraction?
More shells, more shielding, less electrostatic attraction between the nucleus and the outer electrons.
Less shells, less shielding, more electrostatic attraction between the nucleus and the outer electrons.
What is shielding?
The blocking of outermost shell electron attraction by the nucleus, due to the presence of inner-shell.
How is the nuclear charge changing across a period?
Increasing nuclear charge
Which has more shielding, Boron or Aluminium?
Aluminium as it has more shells.
What is happening to the radius across a period?
Shielding is the same (same number of shells), the nuclear charge is increasing (amount of protons), stronger electrostatic attraction between the nucleus and the outermost electrons, radius is decreasing.
What is happening to the radius down a group?
Shielding increases (more shells), less attraction between the nucleus and the outer electrons, radius increases.
What is happening to the IE across a period?
Shielding is the same (same number of shells), the nuclear charge is increasing (amount of protons), stronger electrostatic attraction between the nucleus and the outermost electrons, more energy is required to remove the outermost electron.
What is happening to the IE down a group?
Shielding increases (more shells), less electrostatic attraction between the nucleus and the outermost electron, less energy to remove the uttermost electron. IE decreases.
Why does the first ionisation energy decrease down a group?
Shielding increases (more shells), less electrostatic attraction between the nucleus and the outermost electron, less energy to remove the outermost electron.
What is the trend in IE from Li to Ne?
Shielding is the same (same number of shells), the nuclear charge is increasing (amount of protons), stronger electrostatic attraction between the nucleus and the outermost electrons, more energy is required to remove the outermost electron.
Which is the smaller, Na+ or Mg?
A Na+ ion only has less shells
Its electron are closer to the nucleus and there is less shielding
So the outer electrons are more strongly attracted to the nucleus
The second electron of K is removed from an ion that already has a positive charge. What will this mean for IE?
The second ionisation would be higher.
Which has a greater first IE, Be or Mg?
Be
Be has less shielding than Mg, stronger electrostatic attraction between the nucleus and the outermost electrons, more energy is required to remove the outermost electron.
Why is the second ionisation energy of C higher than the first?
The second electron is removed from an ion that already has a positive charge.
From Na to Ar the ionisation energy is increasing. Why?
Shielding is the same (same number of shells), the nuclear charge is increasing (amount of protons), stronger electrostatic attraction between the nucleus and the outermost electrons, more energy is required to remove the outermost electron.
The electrostatic attraction changes with changing shielding. Why?
More shells, more shielding, less electrostatic attraction between the nucleus and the outer electrons.
Less shells, less shielding, more electrostatic attraction between the nucleus and the outer electrons.
Why does the first IE increase across a period?
Shielding is the same (same number of shells), the nuclear charge is increasing (amount of protons), stronger electrostatic attraction between the nucleus and the outermost electrons, more energy is required to remove the outermost electron.
Which is the smaller ion Be2+ or O2-?
A Be2+ ion only has one shell
Its electron are closer to the nucleus and there is less shielding
So the outer electrons are more strongly attracted to the nucleus
