periodicity onwards Flashcards
Define first ionisation energy
Amount of energy required to remove one mole of electrons from one mole of gaseous atoms to get one mole of gaseous 1+ ions
Describe general trend of first ionisation energy down a group
decrease
Describe general trend of first ionisation energy across a period
increase
Factors that affect ionisation energy?
Nuclear attraction, nuclear charge ,shielding, atomic radius
Why does ionisation energy decrease down a group
More shielding due to more shells, higher atomic radius, and this outweighs the greater nuclear charge. All this decreases nuclear attraction so less energy is required to ionise
Why does ionisation energy increase across a period
Atomic radius decreases as more protons are added while the number of shells remains the same, Nuclear charge pulls the electrons inward. Increases attraction. Shielding is similar. So nuclear attraction is higher. So more energy required to ionise
Complete the sentence: Halogens are in the (???) block of the periodic table
p
Why is the first ionisation energy decrease from N -> O and P -> S, even though its supposed to go up?
Electrons start to pair up within their orbitals, which repel each other slightly, so less energy is required to ionise
Define orbital
A region around nucleus capable of holding up to 2 electrons with opposite spins.
Why does first ionisation energy decrease from Be –> B
p orbital energy > s orbital energy.
What’s the trend in successive ionisation energies
increase within the same shell [less repulsion, and ion is becoming increasingly more positive], large increase between shells [decrease in atomic radius]
What’s the equation for first ionisation energy for element X
X(g) –> X+(g) + e-
What is metallic bonding?
strong electrostatic attraction between cations (positive ions) and delocalised electrons
What is a giant metallic structure
the regular arrangement of positive ions surrounded by a sea of delocalised electrons.
Why can graphene conduct electricity
Each carbon atom is bonded to 3 others so there is a delocalised electron free to move and carry the current
