[ILoveISO]

[Xe] 4f^3         
Atomic number: 59


I thought the element would be Pr+? Since 4f^3 would be Nd and Pr is one back but answer says its Pr2+ how come?

[Grundalizer]

Well since it states in the question, element with atomic number 59, you know right off the bat that it is Pr (Praseodymium).  

If you look at the periodic table, Pr has 5 valence electrons, so it's ground state is [Xe]4f³6s²

So, the Pr ion with the 4f³ electron configuration is when Pr loses its two 6s electrons.  Trends tend to fall apart (sometimes) a little in the larger metals, as energy levels between f/s/d orbitals are all so close (sometimes) the electron configuration might take on illogical or anti-trend configurations just because each element is unique.  If you hadn't been told that it was element with 59 atomic number you could have come up with hundreds of cations of larger metals (although most would not exist in reality).

But anyway, lose the two 6s, that gives you your 4f³

[ILoveISO]

Hm.. ok then but...

The D-block (Transition metals) Are La and Ac apart of it? Because the D-block is 10 elements wide and the F block is 14 elements wide and they are usually separated from the periodic table on the bottom. If I add in La and Ac it makes that whole block have 15 and not 14 elements so my question is are they apart of the F or D blocks? o.o

[Grundalizer]

Ac and La are "d" block elements

Ac = [Rn] 6d1 7s2

La = [Xe] 5d1 6s2

Then the elements in that box they pull out of the periodic table, all 28 of them (14 in each row) are your "f" block ones

[ILoveISO]

Oh if they are D then wouldn't the 4f3 from the last Q mean its Nd, since Ce is first then Pr then Nd?

[Grundalizer]

No, because in your question you state specifically that it is element with atomic number = 59.  Elements can change their number of electrons to form ions, or change their number of neutrons to form isotopes, but they do not change their number of protons.  The #  of protons is like an I.D. tag for elements if you will.  Every element has a specific atomic number that it alone possesses.  So yes, if you did not say in your question that the element was Atomic Number # 59 (Pr) then you could come up with a couple hundred possible ions of other elements that would fit 4f³ as their outter structure.  The key was that it said A.N. = 59 (Pr)

Nd has atomic number = 60