Answer:
option d
Step-by-step explanation:
isotope means atoms with different mass no. 17 and 18 written on the left represent mass number
this is because atoms can differ in mass no.
- option a is incorrect as they have different mass no,hence,different mass
- option b is incorrect as atoms-oxygen-17 and oxygen 18-of same element oxygen cannot differ in no of protons
- if they had different no of electons they would have a charge like -1,-2,etc
- option d is correct,because atoms can differ in mass no. isotope means atoms with different mass no. 17 and 18 written on the left represent mass number