Which properties of element depend on the electronic configuration of atoms and which do not
(b) Why the chemical properties of a group are similar Why do they not have identical properties
(c ) Account for the great chemical similarity of the lanthanoid elements (Z =57 to 71)
(d) Select the largest species in each group
(i) `Ti^(2),Ti^(+3)` (ii) `F^(Θ),Ne,Na^(o+)`
(e) Select the species with the largest `IE` in each group
(i )`na,K,Rb` (ii) F,Ne,Na
(f) Which ion has the smallest radius `Li^(o+),Na^(o+),K^(o+) Be^(+2), Mg^(+2)`
(g) Select among the element that has the lowest and highest IE `K, Ca, Se, B, Kr`,
(h) The ionic radii of `S^(2-)` and `Te^(2-)` are and 220 pm respectively Predict the ionic radius of `Se^(2-)` and for `p^(3-)`
(i) In the ionic compound `KF` the `K^(o+)` and `F^(o+)` have practically identical radii, about 134 pm each. Predict the relative atomic radii of 1`K` and `F` .

Explanation

Cemical and many physical properties depend on electonic cofiguration, but nuclear properties do not
(b) Their properties are similar because of similar outermost electrnic configurations . The differnces are due to their differences in size and the magnitude of shielding effect
(c) Their outermost two shells of electrons are alike `(6s^(2)5d^(1-))` or that configuration is very close to the ground state in stability Moreover all the the lanthanides act as if they had this configuration to a great extent
(d) Ti (ii) `F`
(e) Na (ii) Ne
(f) `Be^(2-)` Be is a second period element, thus smaller than the higher period elements. The `Be^(2+)` ion is isoelectronic with `Li^(o+)` but has a greater nuclear charge
(g) K has the lowest `IE` Kr has the highest IE increases along period `(rarr)` being very small for alkali metals and very large for the noble gases
(h) Ionic radius of `Se^(2-)` is the average of those of `S^(2-)` and `Te^(2-)` that is `202 `pm The actual value is `198 pm` The expected radius of `P^(3-)` to be greater than that of `S^(2-)` since two ions are isoelectronic but `P` has one less proton Its actual radius is 212 pm
(i) The atomic radius of `K` should be much greater than 134Pm and that of `F` much smaller since atomic cations are smaller than their parent atoms, while atomic anions are bigger than their parents The observed atomic radius of `K` and `F` are `231` and 64 pm respectively .