Question

The nuclides with same difference of number of neutrons and number of protons are called:

• A. Isomers
  
• B. Isotops
• C. Isodiaphers
  
• D. Isoelectronic species

Answer 1

The correct option is C Isodiaphers

The nuclides with same difference of number of neutrons and number of protons are called Isodiaphers.
In other words, atoms having same isotopic number are called isodiaphers.
Isotopic number (isotopic excess) $=N-Z=A-2Z$
Here N is the number of neutrons, Z is the number of protons or atomic number and A is the mass number.
Following are the pairs of isodiaphers
(1)${}_{92}^{235}U$ and ${}_{90}^{231}Th$
(2) ${}_{19}^{39}K$ and ${}_9^{19}F$
(3) ${}_{29}^{65}Cu$ and ${}_{24}^{55}Cr$