Question

Which of the following has the same number of protons, electrons & neutrons?

• A. ${}_{27}^{54}X$
• B. ${}_{27}^{55}X$
• C. ${}_{26}^{54}X$
• D. ${}_{28}^{55}X$

Answer 1

Answer: (A)

${}_{27}^{54}X$

Element X given in option A i.e. ${}_{27}^{54}X$ has same no. of protons and neutrons and electrons i.e. 27

Number of neutrons=atomic mass-atomic number.