10. **write the complete symbol for an atom with the following characteristics:
|characteristics|atomic symbol (include atomic #, mass #, and charge)|
|----|----|
|a. neutral atom that contains 19 electrons and 20 neutrons|
|b. nitrogen atom with 8 neutrons and 10 electrons|
|c. neutral isotope of (b) with 9 neutrons|
|d. contains 20 protons, 19 electrons, and 22 neutrons|
|e. neutral iodine atom with 181 subatomic particles in its nucleus|
11. use the data table below to answer the following questions. the two isotopes are of unknown element j.
|isotope|atomic mass (amu)|natural abundance|
|----|----|----|
|1|120.90|57.21%|
|2|122.90|42.79%|
a. *calculate the atomic mass of this element and determine its identity. make sure to use significant figures!
b. based on your answer above, complete the table below.
|isotope|nuclear symbol|isotope name|
|----|----|----|
|1|
|2|

Question

Accepted Answer

### 10.
#### a.
# Explanation:
## Step1: Determine the atomic number
For a neutral atom, number of electrons = number of protons. Given 19 electrons, atomic number $Z = 19$, which is potassium (K).
## Step2: Calculate the mass number
Mass number $A=$ number of protons+number of neutrons. Protons = 19, neutrons = 20, so $A=19 + 20=39$. Charge $q = 0$ (neutral atom).
The atomic symbol is $\ce{_{19}^{39}K}$.
#### b.
# Explanation:
## Step1: Determine the atomic number of nitrogen
Nitrogen has an atomic number $Z = 7$.
## Step2: Calculate the mass number
Mass number $A=$ number of protons+number of neutrons. Protons = 7, neutrons = 8, so $A=7 + 8 = 15$.
## Step3: Determine the charge
There are 10 electrons and 7 protons, so the charge $q=7 - 10=- 3$.
The atomic symbol is $\ce{_{7}^{15}N^{3 -}}$.
#### c.
# Explanation:
## Step1: Recall the atomic number of nitrogen
Atomic number of nitrogen $Z = 7$ (unchanged as it's still nitrogen).
## Step2: Calculate the mass number
Protons = 7, neutrons = 9, so $A=7+9 = 16$. Charge $q = 0$ (neutral atom).
The atomic symbol is $\ce{_{7}^{16}N}$.
#### d.
# Explanation:
## Step1: Identify the element by atomic number
With 20 protons, the element is calcium (Ca) since $Z = 20$.
## Step2: Calculate the mass number
Protons = 20, neutrons = 22, so $A=20 + 22=42$.
## Step3: Determine the charge
There are 20 protons and 19 electrons, so the charge $q=20 - 19 = 1$.
The atomic symbol is $\ce{_{20}^{42}Ca^{+}}$.
#### e.
# Explanation:
## Step1: Determine the atomic number of iodine
Iodine has an atomic number $Z = 53$.
## Step2: Calculate the number of neutrons
The number of sub - atomic particles in the nucleus is the sum of protons and neutrons. Protons = 53 (for iodine), and total sub - atomic particles in the nucleus $=181$. So number of neutrons $n=181 - 53 = 128$. Mass number $A=53+128 = 181$. Charge $q = 0$ (neutral atom).
The atomic symbol is $\ce{_{53}^{181}I}$.

### 11.
#### a.
# Explanation:
## Step1: Use the formula for average atomic mass
The formula for the average atomic mass $M$ of an element with two isotopes is $M = M_1\times\%_1+M_2\times\%_2$, where $M_1$ and $M_2$ are the atomic masses of the isotopes and $\%_1$ and $\%_2$ are their natural abundances as decimals.
$\%_1=0.5721$, $M_1 = 120.90$ amu, $\%_2=0.4279$, $M_2 = 122.90$ amu.
$$
\begin{align*}
M&=(120.90\times0.5721)+(122.90\times0.4279)\
&=120.90\times0.5721+122.90\times(1 - 0.5721)\
&=120.90\times0.5721+122.90\times0.4279\
&=69.16689+52.58891\
&=121.7558\approx121.76\text{ amu}
\end{align*}
$$
The element with an average atomic mass of approximately 121.76 amu is antimony (Sb).
# Answer:
The atomic mass of the element is 121.76 amu and the element is antimony (Sb).
#### b.
For isotope 1:
Nuclear symbol: $\ce{_{51}^{121}Sb}$ (since $Z = 51$ for antimony and $A = 120.90\approx121$), isotope name: Antimony - 121.
For isotope 2:
Nuclear symbol: $\ce{_{51}^{123}Sb}$ (since $Z = 51$ for antimony and $A = 122.90\approx123$), isotope name: Antimony - 123.
# Answer:
Isotope 1: Nuclear symbol $\ce{_{51}^{121}Sb}$, Isotope name Antimony - 121
Isotope 2: Nuclear symbol $\ce{_{51}^{123}Sb}$, Isotope name Antimony - 123

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QUESTION IMAGE

Question

Explanation:

10.

a.

Step1: Determine the atomic number

Step2: Calculate the mass number

b.

Step1: Determine the atomic number of nitrogen

Step2: Calculate the mass number

Step3: Determine the charge

c.

Step1: Recall the atomic number of nitrogen

Step2: Calculate the mass number

d.

Answer:

b.