Question

Complete Table 4.1 on the basis of information available in the symbols given below (a) ${}_{17}{}^{35}Cl$ (b) ${}_6{}^{12}C$ (c) ${}_{35}{}^{81}Br$

(a) ${}_{17}{}^{35}Cl$ (b) ${}_6{}^{12}C$ (c) ${}_{35}{}^{81}Br$

Element	np	nn

Answer 1

Complete the table:

• Every atom has neutron and proton that are present inside the nucleus.
• Number of protons is represented by the atomic number of the element.
• Number of neutrons is obtained by subtracting the atomic number from the mass number of the element.
• While writing the element with its atomic number and mass number, the atomic number is represented by the number written in the subscript, and the mass number is represented by the number written in the superscript.

For Chlorine:

• The atomic number is represented by 17 and thus the number of protons (np) is 17.
• For finding out the number of neutrons, we shall subtract the atomic number from the mass number-
• $n_n=35-17=18$
• So, the number of neutrons is 18.

For Carbon:

• The atomic number is represented by 6 and thus the number of protons (np) is 6.
• For finding out the number of neutrons, we shall subtract the atomic number from the mass number-
• $n_n=12-6=6$
• So, the number of neutrons is 6.

For Bromine:

• The atomic number is represented by 35 and thus the number of protons (np) is 35.
• For finding out the number of neutrons, we shall subtract the atomic number from the mass number-
• $n_n=81-35=46$
• So, the number of neutrons is 46.

Element	${\mathbf{n}}_{\mathbf{p}}$	${\mathbf{n}}_{\mathbf{n}}$
${}_{17}{}^{35}Cl$	17	17
${}_6{}^{12}C$	6	6
${}_{35}{}^{81}Br$	35	46