select the point of isotones from the following nuclei `""._(12)Mg^(24),""._(1)H^(3),""._(2)He^(4),""._(11)Na^(23)`.

Explanation

isotones have same number of neutrons ,N=A-Z
`(i) ""_(1)H^(3) and ""_(2)He^(4)`
number of neutrons `=3-1or 4-2=2`
`(i) ""_(12)mg^(24) and ""_(11)Na^(23)`
number of neutrons `=24-12or 23-11=12`
note :- Nucleri having same mass number A but with proton number (z) and neutron number (A-Z) intercharged are called mirror nucleri
e.g., `""_(1)H^(3)and ""_(2)H^(3) ,""_(3) Li^(7) and ""_(4)Be^(7)`.