HW 8-12 Size Trends involving ions Periodic Trends HW 8-12 Size Trends involving ions

Size of Neutral Atom vs + Ion

+ ion has lost an energy level compared to neutral atom

Size comparison +1 vs +2 ion

Size comparison +1 vs +2 ion +4 +3

Size comparison +1 vs +2 ion +4 +3 Same electron configuration (1s2); Different # of protons; 4 protons of Be+2 exerts stronger attraction than 3 protons of Li+1

Ionic Radii Same trend as atoms, only with negative ions (anions) larger than positive ions (cations).

Size of neutral atom vs negative ion Protons: e- config: 9 9 1s22s22p5 1s22s22p6 Same # of protons; 9 electrons vs 10 electrons. More repulsion within e- cloud with greater number of electrons spreads out e- cloud = bigger Link to Phet Charges

Ion vs. Atom Size

9 10 11 More protons pulling on same # of electrons = smaller atom Isoelectronic Series An isoelectronic series contains atoms/ions with the same number of electrons. F-1: # protons = Ne: # protons = Na+1: # protons = 9 10 11 More protons pulling on same # of electrons = smaller atom

F-1, Ne, and Na+1 all have ______ electrons. Isoelectronic Series An isoelectronic series contains atoms/ions with the same number of electrons. For example, F-1, Ne, and Na+1 all have ______ electrons. When comparing the atomic radii in such a series, the key is to look at the number protons for each: The greater the number of protons pulling on the same number of electrons, the ______________ the radius. _______ > _______ > _______ 10 smaller F-1 Ne Na+1

Video solution to problem #4 Mg+2, Al+3, N-3, O-2 Isoelectronic Series Video solution to problem #4 Mg+2, Al+3, N-3, O-2 Animation 5) Br-1 > Kr > Rb+1 Ratio of P/e-: Br: 35:36 Kr: 36:36 Rb: 37:36 Increased + charge relative to – decreases size