2.12 periodic trends in atomic properties Flashcards
which e- is removed first?
the one bound least tightly aka, the highest E e-
define ionization energy
the E required to remove an e- from a gaseous atom or ion:
X(g) —->X+(g) + e-
I1, the first ionization E is the E required to remove the ________ e- of an atom
highest E
why are the values of subsequent ionization energies (after the first) so much bigger
the first e- is removed from a neutral atom, however, subsequent e-‘s are removed from atoms with increasingly higher (+) charge thus requiring more E to separate from the nucleus
which ionization energy value is the highest and why?
the ionization E required to remove a core e- is the highest because core e- are bound much more tightly than valence e-‘s
first ionization energy (I1) increases moving across a period from:
left to right
going down a group on the PTE, the I1
decreases
as (n) increases, the size of the orbital increases and the e- is _______ to remove
easier
X(g) + e- —–> X-(g)
electron affinity
the addition of an e- can result in either a _______ E or a _______ E
lower or higher E
if the addition of an e- results in a lower E state, the value for e- affinity will be
negative
if the addition of an e- results in a _______ E state, the e- affinity value will be positive
higher
covalent atomic radii
the atomic radii determined by measuring the distance between the nuclei in a diatomic molecule (then dividing by 2)
metallic radii
the radii for metal atoms determined by by measuring the distance between the radii in solid metal crystals
atomic radii for nonmetallic atoms that don’t form diatomic molecules
estimated from various covalent compounds
why do atomic radii decrease going from left to right?
there is decreased shielding going from left to right–the valence e- are drawn closer to the nucleus, decreasing the size of the atom
because of increases in orbital sizes in successive principle quantum levels, atomic radii increase going
down a group
