Chapter 3, Problem 45A

Interpretation Introduction

Interpretation:

The total number of electrons that given ions contain needs to be determined.

Concept Introduction :

An element is composed of the same types of atoms. The neutron and protons present together in the nucleus and the number of the electron is equal to the number of protons when the element is in the neutral state.

Answer to Problem 45A

The total number of the electron in ions-

  ${\text{Al}}^{\text{+3}}$ = $\text{10}$${\text{Fe}}^{\text{+3}}$ = $\text{23}$${\text{Mg}}^{\text{2+}}$ = $\text{10}$${\text{Sn}}^{\text{2+}}$ = $\text{48}$${\text{Co}}^{\text{2+}}$ = $\text{25}$${\text{Co}}^{\text{3+}}$ = $\text{24}$${\text{Li}}^{\text{+1}}$ = $\text{2}$${\text{Cr}}^{\text{3+}}$ = $\text{21}$${\text{Rb}}^{\text{+}}$ = $\text{36}$${\text{Pt}}^{\text{2+}}$ = $\text{76}$ .

Explanation of Solution

Ions − it is a charge form on an element, the $\text{(+)}$ sign is denoted that one electron is lost by the element, and the $\text{(-)}$ sign is denoted that one electron is gain by the element.

The numbers of protons are not equal to the electrons in an ionic form of the electron. The numbers of electrons can be changed with the loss or gain of the electrons.

1. ${\text{Al}}^{\text{+3}}$

$\text{Al}\left(\text{atomic number-13}\right)$ elemental state of aluminum, but ${\text{Al}}^{\text{+3}}$ represents the ionic form of aluminum where $\text{(+)}$ charge explains that $\text{3}$ electrons are lost by the aluminum, so the total number of electrons= $\text{10}$ .

2. ${\text{Fe}}^{\text{+3}}$

$\text{Fe}\left(\text{atomic number 26}\right)$ elemental state of iron, but ${\text{Fe}}^{\text{+3}}$ represents the ionic form of iron where $\text{(+)}$ charge explains that $\text{3}$ electrons lost by the iron, so the total number of electrons= $\text{23}$ .

3. ${\text{Mg}}^{\text{2+}}$

$\text{Mg}\left(\text{atomic number-12}\right)$ elemental state of magnesium, but ${\text{Mg}}^{\text{2+}}$ represents the ionic form of magnesium where $\text{(+)}$ charge explains that $\text{2}$ electrons are lost by the magnesium, so the total number of electrons= $\text{10}$ .

4. ${\text{Sn}}^{\text{2+}}$

$\text{Sn}\left(\text{atomic number}-50\right)$ elemental state of tin, but ${\text{Sn}}^{\text{2+}}$ represents the ionic form of tin where $\text{(+)}$ charge explains that $\text{2}$ electrons are lost by the tin, so the total number of electrons= $\text{48}$ .

5. ${\text{Co}}^{\text{2+}}$

$\text{Co}\left(\text{atomic number}-27\right)$ elemental state of cobalt, but ${\text{Co}}^{\text{2+}}$ represents the ionic form of cobalt where $\text{(+)}$ charge explains that $\text{2}$ electrons are lost by the cobalt, so the total number of electrons= $\text{25}$ .

6. ${\text{Co}}^{\text{3+}}$

$\text{Co}\left(\text{atomic number}-27\right)$ elemental state of cobalt, but ${\text{Co}}^{\text{3+}}$ represents the ionic form of cobalt where $\text{(+)}$ charge explains that $\text{3}$ electrons are lost by the cobalt, so the total number of electrons= $\text{24}$ .

7. ${\text{Li}}^{\text{+1}}$

$\text{Li}\left(\text{atomic number}-3\right)$ elemental state of, but ${\text{Li}}^{\text{+1}}$ is representing the ionic form of lithium where $\text{(+)}$ charge explains that $\text{1}$ electron lost by the lithium, so the total number of electrons= $\text{2}$ .

8. ${\text{Cr}}^{\text{3+}}$

$\text{Cr}\left(\text{atomic number}-24\right)$ elemental state of chromium, but ${\text{Cr}}^{\text{3+}}$ represents the ionic form of chromium where $\text{(+)}$ charge explains that $\text{3}$ electrons are lost by the chromium, so the total number of electrons= $\text{21}$ .

9. ${\text{Rb}}^{\text{+}}$

$\text{Rb}\left(\text{atomic number}-37\right)$ elemental state of rubidium, but ${\text{Rb}}^{\text{+}}$ is representing the ionic form of rubidium where $\text{(+)}$ charge explains that $\text{1}$ electron is lost by the rubidium, so the total number of electrons= $\text{36}$ .

10. ${\text{Pt}}^{\text{2+}}$

$\text{Pt}\left(\text{atomic number}-78\right)$ elemental state of platinum, but ${\text{Pt}}^{\text{2+}}$ is representing the ionic form of platinum where $\text{(+)}$ charge explains that $\text{2}$ electrons are lost by the platinum, so the total number of electrons= $\text{76}$ .

Conclusion

The total number of electrons changes in the ionic form of elements. The number of lost or gain electrons are written in the charged form. The positive charge means the loss of electrons and the negative charge means the gain of electrons.