2. Elements Flashcards
Atomic radius vs ionic radius
Radius of neutral atom; characterized by number of both valence e- and e- shells, number of neutrons don’t matter vs size of charged atoms; cations are smaller than neutral atoms and anions are larger than neutral atoms
Effective nuclear charge (Zeff)
Electrostatic attraction b/w nucleus and outermost e- (aka valence e-); the greater # of p+ in nucleus —> the greater force to pull e- —> e- cloud = closer and binds more tightly to nucleus. HIGHER NET POS CHARGE —> STRONGER Zeff. Calculate it by number of p+ minus number of core e-
Can be affected by shielding effect
Atomic radius trend in periodic table
Inc down a group and left a period. Atomic radius = inversely related to electrostatic force
Ionization energy/ionization potential. First vs second ionization energy
Energy required to remove e- from atom (typically becoming a cation); requires heat —> ENDOTHERMIC PROCESS; lower IE —> easier to remove e- —> more reactive. Energy required to remove first e- vs energy required to remove second e-; second IE is always greater than first cuz it takes a lot of effort to overcome a larger electrostatic force
Electron affinity
The opposite of ionization energy: amount of energy needed by an atom to gain an e- (typically to become an anion). EA can be pos (ex: alkali metals gaining e-) or neg (ex: halogens gaining e-)
EA = stronger when atoms needs 1 or 2 e- to reach noble gas state. Also, smaller atoms have higher EA
Electronegativity and Pauling electronegativity scale. Which elements have zero electronegativity?
Attractive force that an atom will exert in a chemical bond; inc up a group and across a period. Scale to measure electronegativity from 0.7 for Cs to 4 for fluorine. Noble gases have zero electroneg
Electronegativity for Cs vs F
Smallest electronegativity: 0.7, smallest ionization energy, least exothermic e- affinity
vs
Biggest electronegativity: 4, highest ionization energy, highest exothermic e- affinity
All trends on periodic table
Electronegativity, ionization energy, e- affinity, electrostatic force, nonmetallic properties inc up a group and to the right of a period
Atomic radius, metallic properties, nucleophilicity inc down a group and to the left of period
Ionic radius is variable, but cations = smaller than anions of same element b/c you lost e-
Good leaving group, electrostatic forces (due to Zeff eqn), and acidity inc down and right; basicity dec down and right
What/Where are alkali vs alkaline earth metals vs chalcogens vs halogens vs noble gases? What are their characteristics?
First group, highly reactive b/c so close to noble gas config (except H) vs second group vs Group 16, Groups of nonmetals and metalloids vs Group 17, highly reactive b/c so close to noble gas config, highly electronegative, diatomic at standard conditions; F and Cl = gas at standard conditions, Br = liq and I = solid at standard conditions vs last group/Group 18, least reactive —> stable, monoatomic at standard conditions
A vs B elements
Representative elements, have valence e- in their s or p subshells, generally abundant vs nonrepresentative elements, include transition metals (valence e- in s and d subshells) and lanthanides & actinides (valence e- in s and f subshells), generally not abundant except iron and titanium. Transition metals = responsible for diff colored cmpds
Electrostatic force
Attractive force b/w nucleus and valence e-; inc up and right on periodic table
Most electronegative elements
F, O, N, Cl, Br, I, S, C, H
