Q. 6.114 - An Introduction to General, Organic, and Biological Chemistry

Question

One of the ions of gold is gold($III$). ($6.1, 6.2, 6.3, 6.4$)

a. What is the symbol for this ion?

b. How many protons and electrons are in the ion?

c. What is the formula of gold($III$) sulfate? 

d. What is the formula of gold($III$) nitrate?

Step-by-Step Solution

Answer

(a) The symbol of the given ion is ${\mathrm{Au}}^{3+}$

(b) No. of protons are $79$ and no. of electrons are $76$

(c) The required formula is, ${\mathrm{Au}}_2{\left({\mathrm{SO}}_4\right)}_3$

(d) The required formula is, $\mathrm{Au}{\left({\mathrm{NO}}_3\right)}_3$

Part (a) Step 1: Given information

We need to find the symbol of given ion i.e. gold($III$)

Part (a) Step 2: Explanation

We know that

$\mathrm{Au}$ is the Symbol of gold

And according to the given name of ion $+3$ is the charge on gold

Therefore, The required symbol of given ion is,

    ${\mathrm{Au}}^{3+}$ 

Part (b) Step 1: given information

We need to find the no. of protons and no. of electrons 

Part (b) Step 2: Explanation

We know that

Atomic no. of gold is, $79$

And no. of protons are equal to atomic no. 

So, no. of protons are, $79$

And given charge is $3+$

So, no. of electrons are equal to difference of no. of protons and charge 

$79-3=76$

Part (c) Step 1: Given information

We need to find the formula of gold($III$) sulfate

Part (c) Step 2: Explanation

From part (a)

Symbol of gold ion is, ${\mathrm{Au}}^{3+}$

We know that 

Symbol of sulfate ion is, ${\mathrm{SO}}_4^{2-}$

Therefore, required formula is, ${\mathrm{Au}}_2{\left({\mathrm{SO}}_4\right)}_3$

Part (d) Step 1: Given information

We need to find the formula of gold($III$) nitrate

Part (d) Step 2: Explanation

From part (a)

Symbol of gold ion is, ${\mathrm{Au}}^{3+}$

We know that 

Symbol of nitrate ion is, ${\mathrm{NO}}_3^{-}$

Therefore, required formula is, $\mathrm{Au}{\left({\mathrm{NO}}_3\right)}_3$