Periodicity Flashcards
What happens to the atomic radius as you go across period 3?
It decreases. This is because the nuclear charge increases and the shielding stays relatively the same. This means that the attraction between the nucleus and the electrons increases and the shells are pulled inwards.
Describe what happens to the melting points as you go across Period 3.
What is the trend in ionization energy as you go across period 3?
It increases. This is because the atomic radius decreases and the nuclear charge increases. This means that the electrostatic forces of attraction between the nucleus and the outer electrons increase and more energy is needed to remove the electron.
Why does the first ionization energy decrease from magnesium to aluminum?
The outer electron in aluminium is a p-subshell and in magnesium, it is a s-subshell. Since the p-subshell is higher in energy it is easier to remove an electron from it.
Why does the first ionisation energy decrease from phosphorous to sulfur?
The outer electron is sulfur shares an orbital with another electron and phosphorous does not. This makes it easier to remove an electron from sulfur due to the spin-pair repulsion.
