Question

part b: atomic calculations

1. label the information provided in the periodic table.
2. what does the atomic number represent?

________ or ________

1. what does the atomic mass represent?

________ + ________

1. how would you figure the number of protons or electrons in an atom?
2. how would you figure the number of neutrons in an atom?
3. use your knowledge of atomic calculations to complete the chart.

Explanation:

Step1: Labeling the periodic table information

• The atomic number is the number at the top of the element box. So, for oxygen ($O$), the atomic number is $8$.
• The chemical symbol is the one - or two - letter abbreviation. For oxygen, it is $O$.
• The element name is written in full. For oxygen, it is “Oxygen”.
• The atomic mass is the number at the bottom of the element box. For oxygen, it is $15.999$.

Step2: Understanding atomic number

The atomic number represents the number of protons in an atom. In a neutral atom, it also represents the number of electrons.

Step3: Understanding atomic mass

The atomic mass represents the sum of the number of protons and neutrons in an atom.

Step4: Finding the number of protons or electrons

In a neutral atom, the number of protons or electrons is equal to the atomic number.

Step5: Finding the number of neutrons

The number of neutrons is found by subtracting the atomic number from the atomic mass ($\text{Neutrons}=\text{Atomic Mass}-\text{Atomic Number}$)

Step6: Completing the chart for $Li$

• Protons: Since the atomic number of $Li$ is $3$, the number of protons is $3$.
• Neutrons: $\text{Neutrons}=7 - 3=4$
• Electrons: In a neutral atom, electrons = protons = $3$

Step7: Completing the chart for $P$

• Protons: Atomic number is $15$, so protons = $15$
• Neutrons: $\text{Neutrons}=31 - 15 = 16$
• Electrons: Electrons = protons = $15$

Step8: Completing the chart for $Cl$

• Atomic number: Since protons = $17$, atomic number = $17$
• Neutrons: $\text{Neutrons}=35 - 17=18$
• Electrons: Electrons = protons = $17$

Step9: Completing the chart for $Ni$

• Atomic mass: $\text{Atomic Mass}=\text{Protons}+\text{Neutrons}=28 + 31=59$
• Electrons: Electrons = protons = $28$

Step10: Completing the chart for $K$

• Atomic number: Since electrons = $19$, atomic number = $19$
• Protons: Protons = electrons = $19$
• Neutrons: $\text{Neutrons}=39 - 19=20$

Step11: Completing the chart for $Ag$

• Atomic mass: $\text{Atomic Mass}=\text{Protons}+\text{Neutrons}=47+61 = 108$
• Electrons: Electrons = protons = $47$

Step12: Completing the chart for $H$

• Atomic number: Protons = $1$, so atomic number = $1$
• Neutrons: $\text{Neutrons}=1 - 1=0$

Step13: Completing the chart for $Si$

• Atomic number: $\text{Atomic Number}=\text{Electrons}=14$
• Protons: Protons = electrons = $14$
• Atomic mass: $\text{Atomic Mass}=\text{Protons}+\text{Neutrons}=14 + 14=28$

Step14: Completing the chart for $W$

• Atomic number: Protons = $74$, so atomic number = $74$
• Atomic mass: $\text{Atomic Mass}=\text{Protons}+\text{Neutrons}=74+110 = 184$
• Electrons: Electrons = protons = $74$

Step15: Completing the chart for $Ne$

• Atomic number: $\text{Atomic Number}=\text{Electrons}=10$
• Protons: Protons = electrons = $10$
• Atomic mass: $\text{Atomic Mass}=\text{Protons}+\text{Neutrons}=10 + 10=20$

Answer:

Element	Atomic Number	Atomic Mass	Protons	Neutrons	Electrons
$P$	$15$	$31$	$15$	$16$	$15$
$Cl$	$17$	$35$	$17$	$18$	$17$
$Ni$	$28$	$59$	$28$	$31$	$28$
$K$	$19$	$39$	$19$	$20$	$19$
$Ag$	$47$	$108$	$47$	$61$	$47$
$H$	$1$	$1$	$1$	$0$	$1$
$Si$	$14$	$28$	$14$	$14$	$14$
$W$	$74$	$184$	$74$	$110$	$74$
$Ne$	$10$	$20$	$10$	$10$	$10$