Chapter 7, Problem 6STP

Interpretation Introduction

Interpretation: The correct option needs to be chosen from the given choices when the phosphorus element forms an ion.

Concept Introduction: An atom can lose or gain electron/s to attain noble gas electron configuration. A cation or positive charge ion is formed when an atom loses electron/s similarly, an anion or negative charge ion is formed when an atom gain electron/s.

Answer to Problem 6STP

The correct choice is option (C) that is gains three electrons.

Explanation of Solution

Reason for correct choice/s:

The given element is phosphorus. It belongs to group 15 and its atomic number is 15. The electronic configuration of phosphorus is as follows:

  $1s^{2}2s^{2}2p^{6}3s^{2}3p^3$

Here, the valence shell is $3s3p$ thus, the electrons present in it are called valence electrons. The number of valence electrons of phosphorus is 5.

Since phosphorus is a non-metal, it gains electrons to form an anion, and to complete the octet it can gain 3 electrons.

Therefore, the correct choice is “gains three electrons”.

Therefore, the correct option is (C).

Conclusion

Reason for incorrect choice/s:

The given element is phosphorus which is a non-metal. Since non-metals tend to be electron deficient, they do not lose electron/s to attain noble gas electron configuration. Therefore, (B) and (D) cannot be correct choices.

Also, phosphorus belongs to group 15 and has 5 valence electrons. If it gains one or two electrons, the octet cannot be completed and it does not attain noble gas configuration. Therefore, (A) and (E) are incorrect choices.