Dec 9, 2010
25
0
New York
Status
Pre-Dental
For the atomic radii, mg2+ has a smaller radii than P, but why?
first off, as a general rule, the more negative the the element, the bigger its radius would be. since Mg 2+ is more positive than P it has a smaller radii. this means that the 12 electrons that would normally fill the Mg orbitals is now reduced to 10 electrons in its radius.
 
Jul 31, 2009
14
0
Status
Pre-Dental
Rule 1. More negative the element, the bigger the radius.
Rule 2. Atomic radii increases as you go right to left and down the periodic table.

So, according to rule 1: Mg2+ is more positive than P, so Mg2+ is smaller than P
also Mg2+ = Ne and Ne is in Group 8 and P is in group 5, therefore P has greater atomic radii than Ne (Mg2+)

Below would be in order of increasing radii

Ca2+ < K+ < Cl- < S2- < p3-
more positive-----> more negative
 
May 14, 2009
5
0
Status
Pre-Dental
Also think about the effective nuclear charge as it explains alot of trends of periodic table. When mg2+ has 10e it has same number of protons which binds them more tightly hence smaller whereas in an anion number of electrons is increased and nuclear charge is less