Question

attendance question

1. the notation for an isotope of oxygen is shown below.

using lines, match each part of the notation with its meaning.

part of the notation	meaning
6	symbol of the element
3	atomic number

1. lithium has two stable isotopes - lithium - 6 and lithium - 7.

(a) the relative atomic mass of lithium is 6.94. which isotope, lithium - 6 or lithium - 7, is greater in abundance?
(b) determine the number of protons, neutrons, and electrons in each isotope of lithium.

isotope	mass number of each isotope	atomic number	number of protons	number of electrons	number of neutrons

|lithium - 6|
|lithium - 7|

Explanation:

Step1: Match the notation parts

Li is the symbol of the element. 6 is the mass number. 3 is the atomic number.

Step2: Solve for isotope abundance (a)

Let the abundance of lithium - 6 be $x$, then the abundance of lithium - 7 is $1 - x$. The relative atomic mass formula is $A_r=\sum_{i}A_{r,i}x_i$. So, $6.94 = 6x+7(1 - x)$.
Simplify the equation:
\[

$$\begin{align*} 6.94&=6x + 7-7x\\ 6.94&=7 - x\\ x&=7 - 6.94\\ x&=0.06 \end{align*}$$

\]
The abundance of lithium - 6 is 6% and the abundance of lithium - 7 is $1 - 0.06=94\%$. So lithium - 7 has greater abundance.

Step3: Determine sub - atomic particles (b)

For any neutral atom, the number of protons = atomic number, number of electrons = number of protons, and number of neutrons=mass number - atomic number.
For lithium - 6: Atomic number = 3, so number of protons = 3, number of electrons = 3, number of neutrons=$6 - 3=3$.
For lithium - 7: Atomic number = 3, so number of protons = 3, number of electrons = 3, number of neutrons=$7 - 3 = 4$.

Isotope	Mass number of each isotope	Atomic number	Number of protons	Number of electrons	Number of neutrons
Lithium - 7	7	3	3	3	4

Answer:

1. Li - Symbol of the element; 6 - Mass number; 3 - Atomic number
2. (a) Lithium - 7 has greater abundance. (b) Lithium - 6: Mass number 6, Atomic number 3, Protons 3, Electrons 3, Neutrons 3. Lithium - 7: Mass number 7, Atomic number 3, Protons 3, Electrons 3, Neutrons 4.