Question

ISOTOPES

iodine-127 iodine- 131

atomic #
mass #
number of neutrons
value of Z
value of A
​

Answer 1

Isotope 1

• The atomic number is 53
• The mass number is 127
• The number of neutrons is 74
• Z is 53 and A is 127

Isotope 2

• The atomic number is 53
• The mass number is 131
• The number of neutrons is 78
• Z is 53 and A is 131

Mass number and atomic number of an element

We know that the 127 and the 131 are the mass numbers of the isotopes. The atomic number of iodine that applies to the both isotopes is 53

For isotope 1

Mass number - Atomic number = Number of neutrons

127 - 53 = 74

For isotope 2

Mass number - Atomic number = Number of neutrons

131- 53 = 78