Periodic Trends Flashcards
Periodic Trends:
-Atomic Radius
- Ionization Energy
- Electronegativity
Atomic Radius:
one-half the distance between the nuclei of identical atoms that are bonded together
(ATOMIC RADIUS) going L to R across a period, # of energy levels:
remain the same bc –> the # of p+ increases in the nucleus
–> Increasing positive nuclear charge (pulls e- closer)
(ATOMIC RADIUS) going down a group, each new period:
adds another energy level + increases the radius of the atom
Ionization energy:
the energy required to remove one e- from an atom
(IONIZATION ENERGY) as atomic raduis decreases across period:
valence e- being removed is closer to positive nucleus (harder to remove)
(IONIZATION ENERGY) as atomic radius increases down the group:
the valence e- being removed is farther from positive nucleus (easier to remove - less energy required)
Electronegativity:
a measure of the ability of an atom in a chemical compound to attract e- from another atom
(ELECTRONEGATIVITY) as atomic radius decreases across the period –>
the + nuclear charge increases making atom’s ability to “pull In” e- much greater
(ELECTRONEGATIVITY) as atomic radius increases down the group –>
valence e- are further from the positive nuclear charge making it difficult for atom to “pull in” e-‘s
Ionic radius:
Metalls: decreases
Nonmetals: increases
(IONIC RADIUS) Metals:
valence e- are lost (removed) to create cations. More p+ than e- causes nucleus to pull in e- closer –> smaller radii than neutral atom
(IONIC RADIUS) Nonmetals:
valence e- are gained (added) to create anions.
More e- than p+ causes ion to expand due to increased repulsive forces
(SUMMARY)
Period Trends (across the period) :
affected by increasing nuclear charge, increasing # of protons but same # of energy levels
(SUMMARY)
Group Trends (down the group):
Affected by shielding
- shielding increases down the group due to increasing # of energy levels
