Periodic trends Flashcards
What is first ionization energy?
The energy required to remove one mole of electrons from one mole of gaseous atoms to form positive ions.
What is the trend for first ionization energy?
It increases as you go up the group and across the period.
What is electron shielding?
When the inner shell electrons block the nuclear charge of the nucleus and so distance becomes the more important factor.
What is electron affinity?
The energy required to detach an electron from a negative ion in the gas phase.
What is atomic radius?
The size of an atom. Across from left to right it decreases and down a group it increases.
How do you estimate nuclear charge?
Subtract the core electrons from the total electrons and then workout the effective nuclear charge.
Trend of ionic radius.
Moving down the group, ionic radius increases.
Moving across the period, ionic radius decreases.
Trend in electron affinity.
Increases up the group and across the period from left to right.
Define electronegativity.
The relative attraction that an atom has for the shared pair of electrons in a covalent bond.
Trend in electronegativity.
Decreases down a group and increases across the period.
Trends in metallic character.
Increases from right to left then downwards.
Metals (ionization values)
Low values and they have a tendency to lose electrons so they tend to become oxidised.
Non-metals (electron affinity)
They have highly negative electron affinities and have the tendency to become reduced (gain electrons)
What does amphoteric mean?
Can be both a base and an acid.
Example of an amphoteric oxide.
Aluminium oxide.
