Question

Using the information in Table 2.2, answer the following questions. In an ion with an unknown charge, the total mass of all the electrons was determined to be $2.55\times {10}^{-26}$, while the total mass of its protons was $5.34\times {10}^{-23}g$. What is the identity and charge of this ion? What is thesymbol and mass number of a neutral atom whose total mass of its electrons is $3.92\times {10}^{-26}g$,while its neutrons have a mass of $9.35\times {10}^{-23}g$?

Short answer

Mass number and symbol of neutral atom are 99 and$\frac{99}{43}Tc$.

Step-by-step solution

Finding the number of electrons in Ion

Total mass of electrons can be denoted as $2.55\times {10}^{-26}g$. The electron number can be denoted as,

$$\begin{gathered} Numberofelectrons=\frac{2.5\times {10}^{-26}}{9.11\times {10}^{-28}} \\ Numberofelectrons=5.34\times {10}^{-23}g \end{gathered}$$

Finding the number of protons in ion

Total mass of proton to the mass of one proton gives the value of proton number.

$$\begin{gathered} Numberofprotons=\frac{5.34\times {10}^{-23}}{1.67\times {10}^{-24}} \\ Numberofprotons=32 \end{gathered}$$

The element with atomic number 32 is Ge. Here, proton number is greater than electron number $G{e}^{4+}$.

Finding the mass number and symbol

Total mass of electrons is $3.92\times {10}^{-26}$. It can be denoted as,

$\begin{array}{rcl}Numberofelectrons& =& \frac{3.92\times {10}^{-26}}{9.11\times {10}^{-28}}\\ Numberofelectron& =& 43\end{array}$

The proton number and electron number is equal. The element with 43 atomic number is Tc.

The number of neutrons can be denoted as,

$$\begin{gathered} Numberofneutrons=\frac{9.35\times {10}^{-23}}{1.67\times {10}^{-24}} \\ Numberofneutrons=56 \end{gathered}$$

The mass number and symbol are 99 and$\frac{99}{43}Tc$.