3.1.1 Periodicity Flashcards
What is periodicity?
A repeating trend across different periods
Elements in the same group have…
Similar chemical and physical properties
Same outer electron configuration (chemical)
Elements in the same period have…
Repeating trends (gradual changes) in their chemical and physical properties as you go across a period
S block =
Group 1 and 2
P block =
Groups 3,4,5,6,7,0
D block =
Transition metals
What does the classification of elements into orbital explain?
It tells a student what orbital the highest energy electron is in.
As you move across a period……
Nuclear charge increases/Atomic number increases
The increased number of protons causes electrons in their designated shells to become more attracted to the positive nucleus, pulling the electrons closer to the nucleus.
What is the definition of first ionisation energy?
The energy needed to remove 1 electron from each atom of an element in 1 mole of gaseous atoms, to form 1 mole of gaseous ions with a +1 charge.
What is ionisation?
The energy required to form positive ions
Ionisation can only happen in…
In gaseous form
What are the 3 main factors affecting ionisation energy?
Nuclear Charge
Atomic radius
Electron shielding
Nuclear charge (how does it affect ionisation)
The higher the nuclear charge, the higher the ionisation energy
The more protons in nucleus (higher positive charge), the stronger the attraction between the electrons and the nucleus:
Harder to lose an electron, creating a higher ionisation energy.
Atomic Radius (how does it affect ionisation)
The bigger the atom, the weaker the attraction between the outer electron and nucleus (the distance between them increases)
Therefore Lower ionisation energy
Electron shielding (how does it affect ionisation)
The higher the shielding, the lower the ionization energy
The more electrons shielding the outer electron shell from the nucleus, the less energy is required to expel an electron from an atom.
