Ionisation Energies Flashcards
What is the first ionisation energy?
The first ionisation energy is the energy required to remove one electron from each atom in one mole of gaseous atoms of an element to form one mole of gaseous 1+ ions.
What are the three factors affecting ionisation energy?
• Shielding
• Atomic radius
• Charge of the nucleus
What is the atomic radius?
The attraction between the positive nucleus of an atom and its electron orbiting it
How does the atomic radius change across a period?
The atomic radius decreases across a period as the amount of shells increases weakening the attraction
How does the atomic radius change down a group?
The atomic radius increases down the group. This is because the atomic radius and electron shielding increases as a result of the number of shells increasing. This leads to a weaker force of attraction on the outer electrons. Therefore less energy is required to remove them.
How does shielding affect ionisation energy?
The more shells there are in an atoms orbit, less energy is needed to remove the outermost electron as the other shells closer to the nucleus shield the outermost shell from much of the nucleus’s positive attraction.
How does the charge of the nucleus affect ionisation energy?
The stronger the nucleus’s charge, the higher the ionisation energy required. This is because there is a stronger attraction between the positive nucleus and its negatively charged electrons that orbit it.
Is it easier to remove an electron from a P-orbital or from a S-orbital?
It is easier to remove an electron from a P-orbital as there is more repulsion between the electrons, weakening the forces of attraction between the atom’s nucleus and the outermost electrons.
What is the first ionisation energy for carbon?
1st ionisation energy of carbon:
C (g) —> C+ (g) + e-
