Periodicity 3.1.1 Flashcards
What is periodicity?
The repeating patterns of properties across different periods.
What is 1st ionisation energy?
The amount of energy needed to remove 1 mole of electron from 1 mole of gaseous atoms.
The factors that affect 1st IE?
shielding
nuclear charge
nuclear attraction on outmost electron
What is the trend across a period?
Number of shells stay the same so shielding stays the same
nuclear charge inc
e- is added to same shell
greater attraction on outmost e- and positive nuclears
atomic radius decreased
IE energy increases - more energy needed to remove the electron
What is the trend down a group?
Number of electron increase
Number of shells increase
shielding increases
atomic radius increases
nuclear attraction decreases on outer shell
nuclear charge inc but shielding outweighs the effects
less energy needed
so 1st IE decreases
What is the first exception in period 3? why?
MG AND AL
AL has 1 electron on the higher energy 3p sublevel which is further away form the nucleus so more shielding so less energy to remove
What is the second exception in period 3?
S,P
IE of sulfur is less then phospurus
S has an electron that is spin pairing so there is a force of repulsion so less energy needed to remove 1 electron.
Why is second ionisation energy greater then 1st IE?
The proton to electron ratio is greater and the +1 ion is smaller then its normal element.
What does a large jump in IE indicate?
The electron shell is closer to the nucleus
shows the existence of a different energy level
Why is the first ionisation energy of B less then BE
B has removed its electron form a higher energy
so an S electron is lost in BE and a P electron is LOST in B
Predict and explain whether a sodium ion is larger, smaller or the same size as a sodium atom.
Sodium ion is smaller
shell is lost
greater nuclear charge
