Periodicity Flashcards
what is periodicity?
The repeating pattern of properties of elements across different periods in the periodic table
How are elements arranged in?
order of atomic number
How do the elements in period 2 resemble closely to the elements in period 3?
In terms of that repeating chemical behaviour and physical properties, the elements in groups have similar chemical properties
what do elements in the same period have?
A similar electron core
what is the first ionisation energy?
The energy required to move one mole of electrons from one mole of gasesous atoms
What is ionisation?
-The removal of an electron from an atom to make a positive ion
what happens when an electron is removed?
The atom has been ionised
what is generally called the ionisation energy?
Energy needed to remove electrons from the atom
Why is ionisation an endothermic process?
because energy is needed to overcome the electrostatic force of attraction between the negative electron and the positive nucleus
What are the factors influencing the magnitude of ionisation energy?
(attraction)
-nuclear charge
-distance of electrons from nucleus (atomic/ionic radius
-shielding effect
What does more protons mean for nuclear charge?
the greater the nuclear charge
when is nuclear attraction reduced?
With increasing distance (the further, the electron is from the nucleus the easier it is to remove)
How does the shielding affect work?
-inner the shell electrons repel outer of shell electrons
-this repelling effect, reduces the attraction experience by the outer electrons from the nucleus
-Electrons in inner shell shield outer electrons from the attractive force of the nucleus
what happens to ionisation across a period? (NcArss)
-nuclear charge in increases
-outer electron in the same sub shell (atomic radius decreases)
-shielding the same
-Nuclear attraction increases
-Therefore electron requires more energy to remove
-So ionisation energy increases across the period
What happens to ionisation energy down the group?
-nuclear charge increases (outweighed by changes in shielding and shells)
-outer electron in new shell (atomic radius increases)
-Shielding increase
-Nuclear attraction decreases
-therefore electron requires less energy to remove
-So ionisation energy decreases down a group
what does electron repulsion mean?
Electron is easier to remove
What can electronic configurations of elements be predicted from?
successive ionisation energies
what do successive ionisation energy provide?
Evidence for different energy levels