find the element,?

Question

Identify the following element, and justify your answer (use webelements.com for help):

It is capable of forming +3 cations, but is unable to form anions.
It has a first ionization energy of 834 kJ/mol.
It has an electron affinity of 103 kJ/mol.
It has an atomic radius larger than 130 pm.
Its oxide is capable of forming either acids or bases.

Answer 1

Click on the site below to get you to webelements.com. This must be your instructors Periodic Table of choice. Learn to use it.

If "Its oxide is capable of forming either acids or bases," then it is not a metal. Metal oxides are almost always basic. Other than Hydrogen, every element in the blue, pink and green areas are metals. This tells you that you want an element in the yellow area.

Group 18 is the Noble gases. These do not react usually. Group 17 are the Halogens. These are non-metals which usually form negative 1 anions. Now eliminate the man-made elements 113 to 116 because physical data has not been determined (due to short half-lives and high radioactivity).

You are left with 20 elements, 4 each in groups 13 to 16.

If the atomic radius is 130 pm or larger, this eliminates the elements in period I and II (the top two rows). You now have only 12 elements. If you start by clicking on ones toward the center of this block, you can then use the information posted in the topics of the left hand column to find your matches.

Move up or down, right or left, in the Periodic Table until you find the element.

In this case the element is Antimony (symbol Sb).

A faster way to get to the same results from the webelement home page is to click on any element and then go to the bottom of the page where the search engine box is. Type in one of the parameters you need (like 834 kJ/mol for the ionization energy). Click the Dot for a webelement search and not a web search, then click the Search button.

The first listing is for Lithium, but this is for the lattice energy, which is not what you want. The second listing is Antimony and that page give a conformation in that the electron affinity is 103 kJ/mol.

Once you know the element, you can confirm the other parameters.

Answer 2

Perhaps going to webelements.com, as your instructor (or whomever) suggests would be a good idea?

I mean, I went there, and just picked one of your stipulated parameter (ionization energy), coupled with what I know about ionization energy trends, and found the answer in under 10 minutes.

This is the correct answer's electronic configuration.
[Kr].4d10.5s2.5p3

(I won't just hand you the answer).

Go surf at that site, it IS really cool.