Answer:
[tex]\boxed{\text{6.95 u; Li}}[/tex]
Explanation:
1. Atomic mass of T
To get the atomic mass of T, you calculate the weighted average of the atomic masses of the isotopes.
That is, you multiply the atomic mass of each isotope by a number representing its relative importance (e.g.., its percent of the total).
[tex]\begin{array}{ccrcr}\textbf{Atom} & \textbf{Mass/u} &\textbf{Percent} & \textbf{Calculation}& \textbf{Result/u}\\^{6}\text{T}& 6.02 & 7.42 & 6.02 \times 0.0742 & 0.45\\^{7}\text{T}& 7.02 & 92.58 & 7.02 \times 0.9258& 6.50\\& & &\text{TOTAL } = &\textbf{6.95}\\\end{array}[/tex]
2. Identity of T
Lithium has an atomic mass of 6.64 u.
Element T is lithium.
