Chapter U1.12, Problem 6E

Interpretation Introduction

Interpretation: Missing information in the given table is to be filled.

Concept Introduction:

The periodic table is an organized chart of elements. The elements are arranged in groups and periods based on the similarities in their physical and chemical properties. The modern periodic table is a storehouse of information about the elements. The number of vertical columns is 18 which are called groups and there are 7 horizontal rows known as periods. Elements in the middle of the periodic table are not very reactive.

Each element square contains information such as element name, symbol, atomic number and average atomic mass.

Answer to Problem 6E

Element	Chemical symbol	Atomic number	Number of protons	Number of electrons	Number of neutrons	Average atomic mass
Nickel	Ni	28	28	28	31	58.69
Neon	Ne	10	10	10	10	20.18
Magnesium	Mg	12	12	12	12	24.31
Phosphorus	P	15	15	15	16	30.97
Iron/ Manganese	Fe Mn	26 25	26 25	26 25	30 30	55.85 54.94

Explanation of Solution

Given information: The following table is given.

Element	Chemical symbol	Atomic number	Number of protons	Number of electrons	Number of neutrons	Average atomic mass
nickel
	Ne
						24.31
			15
					30

From the periodic table we get the following information about elements:

Element name, symbol, atomic number and average atomic mass

Each square of the periodic table looks like the one given below:

The atomic number gives the number of protons which is also equal to the number of electrons.

Atomic mass is the sum of the number of protons and the number of neutrons.

Number of neutrons = atomic mass − number of protons

1. Element name - Nickel (given)
Symbol- Ni (from the periodic table)

   $\begin{array}{c}\text{Atomic number = 28}\left(\text{from the periodic table}\right)\end{array}$

  $\text{Number of protons = atomic number = 28}$

  $\text{Number of electrons = atomic number = 28}$

 $\text{Average atomic mass = 58}\text{.69 }\left(\text{from table}\right)$

  $\text{Number of neutrons = Average atomic mass }-\text{number of protons}$

           $\text{= 59}-\text{28 }$

           $\text{=31}$

2. Element name - Neon(from the periodic table)
Symbol- Ne (given)

    $\begin{array}{c}\text{Atomic number = 10 }\left(\text{from the periodic table}\right)\end{array}$

   $\text{Number of protons = atomic number = 10}$

   $\text{Number of electrons = atomic number = 10}$

   $\text{Average atomic mass = 20}\text{.18 }\left(\text{from table}\right)$

   $\text{Number of neutrons = Average atomic mass - number of protons}$

            $\text{= 20 - 10}$

            $\text{= 10}$

3. Element name - Magnesium(from the periodic table)
Symbol- Mg (from the periodic table)

   $\begin{array}{c}\text{Atomic number = 12 }\left(\text{from the periodic table}\right)\end{array}$

  $\text{Number of protons = atomic number = 12}$

  $\text{Number of electrons = atomic number = 12}$

 $\text{Average atomic mass = 24}\text{.31 }\left(\text{given}\right)$

 $\text{Number of neutrons = Average atomic mass - number of protons}$

          $\text{= 24- 12}$

          $\text{= 12}$

4. Element name - Phosphorus(from the periodic table)
Symbol- P (from the periodic table)

  $\begin{array}{c}\text{Number of protons = 15 }\left(\text{given}\right)\end{array}$

    $\text{Atomic number = number of protons= 15}$

  $\text{Number of electrons = number of protons = 15}$

 $\text{Average atomic mass = 30}\text{.97 }\left(\text{from table}\right)$

  $\text{Number of neutrons = Average atomic mass - number of protons}$

           $\text{= 31- 15}$

           $\text{= 16}$

There are two elements with the number of neutrons (the difference between atomic mass and atomic number) = 26, iron and manganese.

5. Element name - Iron(from the periodic table)
Symbol- Fe (from the periodic table)

  $\begin{array}{c}\text{Average atomic mass = 55}\text{.85 }\left(\text{from the periodic table}\right)\end{array}$

   $\text{Number of neutrons = 30 }\left(\text{given}\right)$

     $\text{Atomic number = atomic mass - number of neutrons= 56- 30}$

            $\text{= 26}$

    $\text{Number of protons = atomic number}$

            $\text{ = 26}$

   $\text{Number of electrons = atomic number}$

            $\text{ = 26}$

Element name − Manganese(from the periodic table)

Symbol- Mn (from the periodic table)

  $\begin{array}{c}\text{Average atomic mass = 54}\text{.94 }\left(\text{from the periodic table}\right)\end{array}$

  $\text{Number of neutrons = 30 }\left(\text{given}\right)$

    $\text{Atomic number = atomic mass- number of neutrons}$

           $\text{= 55- 30}$

           $\text{= 25}$

   $\text{Number of protons = atomic number}$

           $\text{ = 25}$

  $\text{Number of electrons = atomic number }$

           $\text{= 25}$

Conclusion

The periodic table gives us information such as element name, symbol, atomic number and average atomic mass. The number of protons is equal to the number of electrons and is known as the atomic number. The number of neutrons can be calculated by subtracting the atomic number from the average atomic mass rounded to the nearest whole number.