For Each of the Elements Below, There Are Only Two

Multiple Choice

For each of the elements below, there are only two naturally occurring isotopes.Using the atomic masses on the periodic table, identify the pair in which the heavier isotope is the more abundant one.

A) ⁶³Cu and ⁶⁵Cu
B) ⁸⁵Rb and ⁸⁷Rb
C) ¹⁰B and ¹¹B
D) ⁷⁹Br and ⁸¹Br
E) ¹⁴N and ¹⁵N