1) the element Q has the electronic configuration 1S2, 2S2, 2p6, 3s2, 3p6, 4s2 3d10, 4p1. Write the atomic #. Q exist as 69Q and 71Q. What is the significance of the 2 #'s. What does it mean.

Question

B) find the atomic mass if 69Q is 60% anf 71Q is 40%

Answer 1

A. Count the electrons. #e = # protons = atomic number.
The two numbers are the mass numbers of the two isotopes of element 31.

B. You need the atomic mass for the isotope of 69 and 71. Assuming they are 69 and 71 (that isn't quite correct), that will be
(0.60*69) + (0.40*71) = ?