Q. 7 - An Introduction to General, Organic, and Biological Chemistry

Question

For parts a to f, consider the loss of electrons by atoms of the element $X$, and a gain of electrons by atoms of the element $Y$, if $X$ is in Group $2A\left(2\right)$, Period $3$, and $Y$ is in Group $7A \left(17\right)$, Period $3$. ($4.6, 6.1, 6.2, 6.3, 6.8$)

a. Which reactant has the higher electronegativity? 

b. What are the ionic charges of $X$ and $Y$ in the product?

c. Write the electron arrangements for the atoms $X$ and $Y$.

d. Write the electron arrangements for the ions of $X$ and $Y$.

e. Give the names for the noble gases with the same electron arrangements as each of these ions.

f. Write the formula and name for the ionic compound formed by the ions of $X$ and $Y$.

Step-by-Step Solution

Answer

(a) Reactant $Y$ has higher electronegativity.

(b) Ion charges are data-custom-editor="chemistry" ${\mathrm{X}}^{+2}$ and $Y^{-}$

(c) The electron arrangements of $X$ and $Y$ are $2, 8, 2$ and $2, 8, 7$

(d) The electron arrangements of $X$ and $Y$ ions are $2, 8$ and $2, 8, 8$

(e) Names of noble gases are data-custom-editor="chemistry" $\mathrm{Ne}$ and data-custom-editor="chemistry" $\mathrm{Ar}$

(f) Formula and name for the ionic compound is ${\mathrm{MgCl}}_2$ and magnesium chloride

Part (a) Step 1: Given information

We need to find the reactant with higher electronegativity in the given reaction i.e. 

Part (a) Step 2: Explanation

We know that

Electronegativity is the tendency to gain electrons

As, Reactant $\mathrm{Y}$ gained the electrons

Therefore, reactant $Y$ has higher electronegativity

Part (b) Step 1: Given information

We need to find the ionic charge on the products of reaction

Part (b) Step 2: Explanation

We know that

From the group no. and the period in which the element lies we can know the valence electrons of the element 

As the reactant $X$ has to lose two extra electrons to complete its octet.

Therefore, the Ionic charge on $X$ is $+2$ 

And as the reactant $Y$ has to gain one electron to complete its octet.

Therefore, the Ionic charge on $Y$ is $-1$

Part (c) Step 1: Given information

We need to find the electronic arrangement for the reactant.

Part (c) Step 2: Explanation

We know that

From the given group no. and period of the reactants we can determine their electronic arrangements

Therefore, The electron arrangements of $X$ and $Y$ are $2, 8, 2$ and  $2,8,7$

Part (d) Step 1: Given information

We need to find the electron arrangements for the ions 

Part (d) Step 2: Explanation

From parts (b) and (c) 

We can interpret the electron arrangements for the ions  

Therefore, electron arrangements for the ions $X$ and $Y$ are $2, 8$ and $2, 8, 8$

Part (e) Step 1: Given information

We need to find the names for the noble gases with the same electron arrangements 

Part (e) Step 2: Explanation

We know that

From the electron arrangement of an atom we can determine the corresponding name of the element

As in part (d), We find electron arrangement of ions

So, the Names of noble gases are $\mathrm{Ne}$ and $\mathrm{Ar}$ 

Part (f) Step 1: Given information

We need to find formula and name for the ionic compound formed by the ions.

Part (f) Step 2: Explanation

We know that

By group no. and period we can determine the name of the element 

So, ion of $X$ represents data-custom-editor="chemistry" ${\mathrm{Mg}}^{2+}$(Magnesium ion )

And ion of $Y$ represents data-custom-editor="chemistry" ${\mathrm{Cl}}^{-}$

Therefore, Formula and name for the ionic compound is ${\mathrm{MgCl}}_2$ and magnesium chloride