Chapter 7, Problem 61A

(a)

Interpretation Introduction

Interpretation: The symbol of the ion formed by bromine to attain noble gas electron configuration needs to be determined.

Concept Introduction: An atom of an element can gain or lose electron/s to attain noble gas electron configuration to form positive or negative charged ions respectively. The number of electron/s gain or lose depends on the number of valance electrons. The symbol of an ion has a charge equal to the number of electron/s gained or lost. Here, a cation formed by losing electron/s is positively charged and an anion formed by gaining electron/s is negatively charged.

Answer to Problem 61A

  ${\text{Br}}^{-}$

Explanation of Solution

The given element is bromine. It is a non-metal and belongs to group 17. It has 7 valance electrons thus, only one electron is required to complete the octet. Since it gains an electron, it has a negative charge on its ion or it forms an anion. The number of electrons gained by bromine to form an ion is 1; thus, it has a -1 charge. The symbol of the ion formed by bromine is ${\text{Br}}^{-}$ .

(b)

Interpretation Introduction

Interpretation: The symbol of the ion formed by hydrogen to attain noble gas electron configuration needs to be determined.

Concept Introduction: An atom of an element can gain or lose electron/s to attain noble gas electron configuration to form positive or negative charged ions respectively. The number of electron/s gain or lose depends on the number of valance electrons. The symbol of an ion has a charge equal to the number of electron/s gained or lost. Here, a cation formed by losing electron/s is positively charged and an anion formed by gaining electron/s is negatively charged.

Answer to Problem 61A

  ${\text{H}}^{-}$

Explanation of Solution

The given element is hydrogen. It belongs to group 1. It has 1 valance electron thus, only one electron is required to complete the octet. Since it gains an electron, it has a negative charge on its ion or it forms an anion. The number of electrons gained by hydrogen to form an ion is 1 thus, it has a -1 charge. The symbol of the ion formed by hydrogen is ${\text{H}}^{-}$ .

(c)

Interpretation Introduction

Interpretation: The symbol of the ion formed by arsenic to attain noble gas electron configuration needs to be determined.

Concept Introduction: An atom of an element can gain or lose electron/s to attain noble gas electron configuration to form positive or negative charged ions respectively. The number of electron/s gain or lose depends on the number of valance electrons. The symbol of an ion has a charge equal to the number of electron/s gained or lost. Here, a cation formed by losing electron/s is positively charged and an anion formed by gaining electron/s is negatively charged.

Answer to Problem 61A

  ${\text{As}}^{3-}$

Explanation of Solution

The given element is arsenic. It is a non-metal and belongs to group 15. It has 5 valance electrons thus; three electrons are required to complete the octet. Since it gains an electron, it has a negative charge on its ion or it forms an anion. The number of electrons gain by arsenic to form an ion is 3 thus, it has a -3 charge. The symbol of the ion formed by arsenic is ${\text{As}}^{3-}$ .

(d)

Interpretation Introduction

Interpretation: The symbol of the ion formed by selenium to attain noble gas electron configuration needs to be determined.

Concept Introduction: An atom of an element can gain or lose electron/s to attain noble gas electron configuration to form positive or negative charged ions respectively. The number of electron/s gain or lose depends on the number of valance electrons. The symbol of an ion has a charge equal to the number of electron/s gained or lost. Here, a cation formed by losing electron/s is positively charged and an anion formed by gaining electron/s is negatively charged.

Answer to Problem 61A

  ${\text{Se}}^{2-}$

Explanation of Solution

The given element is selenium. It is a non-metal and belongs to group 16. It has 6 valance electrons; thus, two electrons are required to complete the octet. Since it gains an electron, it has a negative charge on its ion or it forms an anion. The number of electrons gain by selenium to form an ion is 2; thus, it has a -2 charge. The symbol of the ion formed by seleniumis ${\text{Se}}^{2-}$ .