Question

which pair of atoms are isotopes of the same element?
choose 1 answer:
a ( \frac{13}{7}x ) and ( \frac{14}{7}x )
b ( \frac{13}{7}x ) and ( \frac{14}{8}x )
c ( \frac{14}{7}x ) and ( \frac{14}{8}x )

Explanation:

Isotopes are atoms of the same element that have the same atomic number (number of protons) but different mass numbers (sum of protons and neutrons). In the notation \(_{Z}^{A}X\), \(Z\) is the atomic number and \(A\) is the mass number.

• For option A: Both atoms have \(Z = 7\) (same atomic number, so same element) and \(A=13\) and \(A = 14\) (different mass numbers).
• For option B: \(Z=7\) and \(Z = 8\) (different atomic numbers, different elements).
• For option C: \(Z=7\) and \(Z = 8\) (different atomic numbers, different elements).

Answer:

A. \(_{7}^{13}X\) and \(_{7}^{14}X\)