Chapter 4, Problem 7STP

Interpretation Introduction

Interpretation:

The number of neutrons, protons and electron in $Te$ is to be calculated.

Concept introduction:

Atom is the smallest unit of a matter. It is indestructible and cannot be created. It consists of protons, neutrons and electron as subatomic particles.

Answer to Problem 7STP

Correct answer: Option (b) 74 neutrons, 52 protons and 52 electrons.

Explanation of Solution

Reason for correct option:

Tellurium is a chemical element whose atomic number is 52. $Te$ is an isotope of the element, where 126 is the mass number and 52 is the atomic number.

$\text{Atomic number}\text{(Z)=}{\text{Number of electrons (N}}_{\text{e}}\text{)= Number of protons}{\text{(N}}_{\text{p}}\text{) =52}$

$Numberofneutron{\text{(N}}_n\text{)=}\text{Mass}\text{number}-atomicnumber$

$N_n=126-52=74$

Conclusion

Reasons for incorrect options:

Option (a), 126 neutrons, 52 protons and 52 electrons. Number of neutrons is not equal to mass number. Thus, this is an incorrect answer.

Option (c) 52 neutrons, 74 protons and 74 electrons. Number of neutrons is not equal to atomic number, and number of protons and number of neutrons cannot be equal to mass number of the isotope minus atomic number.

Option (d) 52 neutrons, 126 protons and 126 electrons. Number of neutrons is not equal to atomic number, and number of protons and number of neutrons cannot be equal to mass number of the isotope.