Flashcards in Unit 6 Periodic Trends (trends/application) Deck (12):
Trend for atomic radii across a period
It decreases in size because there is a greater proton charge in the nucleus forcing the electrons to get closer to the nuclues
Trend for atomic radii down a group
Increases in size because as energy levels increase outer electrons get farther from the nucleus and are held less tightly
Trend for electron affinity across a period
a general increase (decreases among + ions; increases among -ions), more stable (greater energy charge) as ion approaches meeting octet rule.
Trend for electron affinity down a group (- = energy is released)
a general decrease because as proton charge increases electron affinity and an increase in atomic radii that decreases electron affinities causes it.
Trend for ionization energy across a period
Increases because of increasing proton charge that attracts electrons in the same energy level - it becomes harder to drop electrons as group 15-17 elements what to add electrons, not lose them.Noble gases don't want to lose or gain anything.
Trend for ionization energy down a group
Decreases because electrons down a group are in successively farther energy levels and held less tightly by the nucleus and due to electron shielding - as you go down it's easier to remove an electron
Trend for ionic radii across a period
It decreases thru group 3/13 major increase at group 4/14 then size decreases again because as atoms lose successive electrons, the proton charge is larger and condenses the electron cloud; major increase in size occurs as atoms gain electrons and then size decreases again due to increased proton charge
Trend for ionic radii down a group
increase down a group because of more energy levels
Trend for valence electrons across a period
Increases across a period because atoms are successively filling s and p orbitals - a larger valence shell
Trend for valence electrons down a group
Stays the same; as # of energy levels increase the number of valence electrons stay the same (they are in the same group <-- you know this :) )
Trend for electronegativity across a period
Increases across a period because atoms have greater attraction for electrons as they move towards an attractive electron config