Chapter 15, Problem 4STP

Interpretation Introduction

Interpretation:

The type of ions formed by yttrium needs to be determined.

Concept introduction:

There are two types of ions:

Positive ions

Negative ions

The ions which are formed by loss of electrons are positive ions known as cations.

The ions which are formed by gain of electrons are negative ions known as anions.

Answer to Problem 4STP

A

Explanation of Solution

Yttrium is a metal and metals have tendency to loss electrons because they have extra electrons in their valence shell which are easy to donate.

Atomic number of yttrium is 39

Its electronic configuration is:

$\left[Kr\right]4d^{1}5s^2$

To attain noble gas configuration, yttrium loss three electrons.

Therefore yttrium forms positive ion.

Conclusion

Yttrium is a metal and so it forms positive ions. Therefore option A is correct and other are wrong.

Option D is incorrect because an element whose configuration is noble gas configuration that element has no tendency to loss or gain electrons and not form ions and yttrium has 3 electrons in outermost shell. So it forms positive ions.