Periodicity Flashcards
Define Periodicity
A repeating trend in properties across each period.
What the left hand side block called?
S- BLOCK
Whats the middle block called?
D- block.
Whats the right hand side block called?
P- Block
Define first ionisation energy
The energy required to remove one electron from each atom in 1 mole of gaseous atoms to form 1 mole of gaseous 1+ ions.
What is the general trend in ionisation energy down a group.
The increased nuclear charge is outweighed by increased atomic radius and increased electron shielding so attraction between nucleus and outer Most electrons is weaker.
Therefore ionisation energy decreases down a group.
What is the general trend in ionisation energy across a period?
Ionisation energy increases across a period as increased nuclear charge, but shielding remains constant, leading to a decrease in atomic radius and a stronger attraction between the nucleus and outer electrons.
What is the reason for the dip in ionisation energy from group 2 to 3.
As the electron is being lost from a higher sub level (3p sub level instead of 3s) which has higher energy, Therefore the electron is lost more easily so smaller ionisation energy.
What is the reason for the dip in ionisation energy from group 5 to 6.
As the electron is being lost from an orbital with a paired electron, the electrons repel one another so one of them is lost more easily so it has a lower ionisation energy.
What substances in period 2 and 3 will have giant covalent lattices?
Boron, Carbon and silicon.
Why do substances that have giant covalent lattices have high melting and boiling points.
As we are breaking the strong covalent bonds between the ATOMS.
Why do diamond and silicone not conduct electricity?
As all four outer shell electrons are involved in covalent bonding.
so electrons cannot move and are not available for conducting electricity.
Why do graphite and graphene conduct electricity?
one delocalised electron per cation, the delocalised electrons are able to move therefore conduct electricity.
Why are compounds with giant covalent structure unable to conduct electricity?
As the strong covalent bonds between the atoms are hard to break.
Why are compound with ionic structure soluble in water?
electrostatic attraction between polar water molecules and ions break up the lattice.
