Chapter 39, Problem 28A

(a)

To determine

Ranking of atoms or ions by the number of protons in the nucleus.

Explanation of Solution

Introduction:

The number of protons in the nucleus of an atom is same as the atomic number of the atom. The number of electrons remains equal to the number of electrons in the atom.

The atomic number of oxygen atom is eight. So, the number of protons in the nucleus of oxygen atom is also eight.

The atomic number of fluorine atom is nine. So, the number of protons in the nucleus of the fluorine atom is also nine.

The atomic number of sulphur atom is sixteen. So, the number of protons in the nucleus of sulphur atom is also sixteen.

The atomic number of sodium atom is eleven. So, the number of protons in the nucleus of the oxygen atom is also eleven.

Conclusion:

Thus, the ranking of atoms by the number of protons in the nucleus of atom in decreasing order is C, D, B, A.

(b)

To determine

Ranking of atoms or ions by the number of neutrons in the nucleus.

Explanation of Solution

Introduction:

The sum of the number of protons and number of neutrons is called mass number. The higher is the mass number more is number of neutrons in the nucleus of atom.

The mass number of the oxygen atom is sixteen, so number of neutrons in the nucleus of the oxygen atom is eight.

The mass number of fluorine atom is nineteen. So, the number of protons in the nucleus of fluorine atom is ten.

The mass number of sulphur atom is thirty two. So, the number of protons in the nucleus of sulphur atom is sixteen.

The mass number of sodium atom is twenty three. So, the number of protons in the nucleus of oxygen atom is also twelve.

Conclusion:

Thus, the ranking of atoms by the number of neutrons in the nucleus of atom in decreasing order is C, D, B, A.

(c)

To determine

Ranking of atoms or ions by the number of electrons in the nucleus.

Explanation of Solution

Introduction:

The number of electrons in a normal atom is equal to the number of protons in the nucleus of the atom. The positive charge on the atom is due to loss of one electrons from the number of electrons in the normal atom. The negative charge on the atom due to gain of one electron in the number of electrons in normal atom.

The number of protons in oxygen atom is eight. So, the number of electrons in nucleus of oxygen atom is also eight.

The number of electrons in fluorine atom is nine. So, the number of electrons in the negative fluorine atom becomes ten.

The number of protons in sulphur atom is sixteen. So, the number of electrons in sulphur atom is also sixteen.

The number of electrons in sodium atom is eleven. So, the number of electrons in the positive sodium atom becomes ten.

Conclusion:

Thus, the ranking of atoms by the number of electrons in the atom in decreasing order is C, D = B, A.