Chapter 3.5, Problem 2RQ

(a)

Interpretation Introduction

Interpretation:

The ion formed by fluorine needs to be explained.

Concept Introduction:

Ions are formed by gaining or releasing the electron to or from the valence shell of a neutral atom.

Explanation of Solution

Fluorine is the 7^th group element and it can gain one electron to form 1 -ve ions or anions. One electron is added to the valence shell of a fluorine atom to get a stable electronic configuration like a noble gas. After taking one electron fluorine atom forms an anion (fluoride ion).

Fluorine $\mathrm{F}+e^{-}\to F^{-}$ (fluoride ion)

(b)

Interpretation Introduction

Interpretation:

The ion formed by lithium needs to be explained.

Concept Introduction:

Ions are formed by gaining or releasing the electron to or from the valence shell of a neutral atom.

Explanation of Solution

Lithium is group 1 metal and group 1 atoms release one electron to form 1 +ve ion or cations. One electron is taken out from the valence shell of the lithium atom to get a stable electronic configuration like a noble gas. After releasing one electron, the lithium atom forms a cation (lithium cation).

Lithium $\mathrm{Li}\to {\mathrm{Li}}^{+}+e^{-}$ (lithium cation)