Question

50.0% of the isotopes of an element have a mass of 196 amu and 50.0% of the isotopes have a mass of... avg atomic mass = (abundance as a decimal × mass) +...
a 194 amu
b 197 amu
c 195 amu
d 196 amu

Explanation:

Step1: Identify abundances and masses

50.0% (0.5) of isotopes have 196 amu, and the other 50.0% (0.5) – let's assume the other mass is \( m \), but wait, the problem might have a typo, but looking at options, maybe the other isotope's mass is also 196? Wait, no, maybe the original problem (cut off) has two isotopes: 50% 196 amu and 50% another? Wait, the options include 196. Wait, average atomic mass formula: \( \text{Avg} = (abundance_1 \times mass_1) + (abundance_2 \times mass_2) \). If 50% (0.5) is 196 amu, and 50% (0.5) is, say, if the options are 196, maybe both are 196? Wait, no, maybe the problem was 50% 196 and 50% 196? No, that can't be. Wait, maybe the original problem had two isotopes: 50% 196 and 50% 196? No, that would make average 196. Wait, the options have D as 196 amu. Let's check: if both isotopes are 50% 196, then \( (0.5 \times 196) + (0.5 \times 196) = 196 \). So the average is 196 amu.

Step2: Calculate average atomic mass

Using the formula: \( \text{Avg Atomic Mass} = (0.5 \times 196) + (0.5 \times 196) \) (assuming the other isotope is also 196, or maybe the problem's cut-off part had the same mass? Wait, maybe the original problem was 50% 196 and 50% 196, so average is 196.

Answer:

D. 196 amu