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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: bpeck8 on November 21, 2009, 06:26:18 PM

Title: Various questions.
Post by: bpeck8 on November 21, 2009, 06:26:18 PM

1. Which one of the following elements has the largest radius?

O
F
Al
P
B

I put Al, and got counted wrong. Anyone explain? I dont understand why its wrong.

2. The electron configuration of the two atoms that form isoelectronic ions are _____.
Consider the following electron configurations to answer the questions that follow:
(vi) [Kr]5s1
(vii)[Ne]3s23p5
(viii)[Ar]4s2sd104p4
(ix)[Ne]3s23p6
(x)[Ar]4s1

A.(i) and (iii)
B.(ii) and (iii)
C.(iii) and (iv)
D.(i) and (v)
E.(ii) and (v)

Im not sure what answer this one is. I know that isoelectronic ions are ions that have the same number of electrons, but im not seeing it in this question.

Title: Re: Various questions.
Post by: BetaAmyloid on November 21, 2009, 06:36:55 PM

Try #1 with this: (Trends of Radii)

(https://www.chemicalforums.com/proxy.php?request=http%3A%2F%2Fwww.chem1.com%2Facad%2Fwebtext%2Fatoms%2Fatpt-images%2FPT_covalent_radii.jpg&hash=188928ee9242f7305d6ce5a45830b2ff37406405)

For #2:

Two ions are said to be isoelectronic with each other if they have the same number of valence electrons and the same structure, regardless of the nature of elements involved.

Which of these have the same number of valence electrons?