Question

isotopes
directions: fill in the missing information about the different isotopes of different elements. if all the answers in a row are correct, then the row should change color.

element symbol | element name | atomic number | # protons | # neutrons | # electrons | mass number | isotope notation | isotope name
8 | ca | calcium | 20 | 20 | 20 | | |
9 | i | iodine | 53 | 53 | 74 | 53 | 127 | | iodine 127
10 | | lead-207 | | | | | | |

Explanation:

To solve for the missing information in the isotopes table, we'll analyze each row (Calcium, Iodine, Lead - 207) and use the relationships between atomic number, number of protons, neutrons, electrons, and mass number.

Calcium (Row 8)

Step 1: Recall the relationships

• Atomic number ($Z$) = Number of protons = Number of electrons (in a neutral atom).
• Mass number ($A$) = Number of protons + Number of neutrons.
• Isotope notation: $^{A}_{Z}\text{Symbol}$

Step 2: Find the number of neutrons for Calcium

We know that for Calcium, the atomic number ($Z$) is 20 (so number of protons = 20, number of electrons = 20), and we need to find the number of neutrons. But we first need the mass number. Wait, actually, let's check the given data. Wait, maybe we can find the mass number. Wait, the mass number is protons + neutrons. Wait, but we know that for Calcium, the atomic number is 20, and let's assume we need to find the mass number. Wait, no, maybe the table has some missing cells. Wait, let's re - examine.

Wait, the table for Calcium (row 8):

• Element Symbol: Ca
• Element Name: Calcium
• Atomic Number: 20
• # Protons: 20
• # Electrons: 20
• We need to find # Neutrons and Mass Number and Isotope Notation.

We know that for a common isotope of Calcium, but let's use the formula $A = Z + N$ (where $A$ is mass number, $Z$ is atomic number, $N$ is number of neutrons). Wait, maybe we can find the number of neutrons. Wait, maybe there is a typo or maybe we can calculate. Wait, actually, for Calcium - 40 (a common isotope), number of neutrons $N=A - Z$. If we assume that the mass number is 40 (since $Z = 20$ and a common isotope is Ca - 40), then $N=40 - 20=20$. Wait, but let's check the table structure. Wait, maybe the mass number is protons + neutrons. Wait, we have protons = 20, if we can find neutrons. Wait, maybe the table is missing the mass number and neutrons. Let's calculate:

Mass number ($A$) = number of protons + number of neutrons. But we need to find neutrons. Wait, maybe the problem is to fill in the missing cells. Let's do it step by step.

For Calcium:

• # Neutrons: Let's assume we need to calculate. Wait, maybe the mass number is 40 (since Ca - 40 is a common isotope). So $N=A - Z=40 - 20 = 20$.
• Mass Number: 40 (since $A = Z+N=20 + 20=40$)
• Isotope Notation: $^{40}_{20}\text{Ca}$
• Isotope Name: Calcium - 40

Iodine (Row 9)

• Element Symbol: I (since element name is Iodine)
• # Neutrons: 74 (given)
• Atomic Number: 53 (given), so # Protons = 53, # Electrons = 53 (neutral atom)
• Mass Number ($A$) = # Protons + # Neutrons = $53+74 = 127$
• Isotope Notation: $^{127}_{53}\text{I}$
• Isotope Name: Iodine - 127 (already given as Iodine 127)

Lead - 207 (Row 10)

• Element Name: Lead
• Isotope Name: Lead - 207, so Mass Number ($A$) = 207
• Lead has an atomic number ($Z$) of 82 (from periodic table knowledge). So:
• # Protons = 82
• # Electrons = 82 (neutral atom)
• # Neutrons = $A - Z=207 - 82 = 125$
• Element Symbol: Pb
• Atomic Number: 82
• Isotope Notation: $^{207}_{82}\text{Pb}$

Filling the table (summary for each row)

Row 8 (Calcium)

• # Neutrons: $40 - 20=20$
• Mass Number: $20 + 20 = 40$
• Isotope Notation: $^{40}_{20}\text{Ca}$
• Isotope Name: Calcium - 40

Row 9 (Iodine)

• Element Symbol: I
• Mass Number: $53+74 = 127$
• Isotope Notation: $^{127}_{53}\text{I}$

Row 10 (Lead - 207)

• Element Symbol: Pb
• Atomic Number: 82
• # Protons: 82
• # Neutrons: $207 - 82 = 125$
• # Electrons: 82
• Mass Number: 207
• Isotope Notation: $^{207}_{82}\text{Pb}$

If we take…

Step 1: Recall the formula for mass number

The mass number $A$ of an atom is given by the sum of the number of protons ($Z$) and neutrons ($N$), i.e., $A=Z + N$. For a neutral atom, the number of protons is equal to the atomic number, and the number of electrons is equal to the number of protons. For Calcium, the atomic number $Z = 20$ (so number of protons = 20, number of electrons = 20). A common isotope of Calcium is Calcium - 40, so $A = 40$.

Step 2: Calculate the number of neutrons

Using the formula $N=A - Z$, substitute $A = 40$ and $Z = 20$. So $N=40 - 20=20$.

Answer:

For Calcium, the number of neutrons is 20, mass number is 40, isotope notation is $^{40}_{20}\text{Ca}$, and isotope name is Calcium - 40. For Iodine, element symbol is I, mass number is 127, isotope notation is $^{127}_{53}\text{I}$. For Lead - 207, element symbol is Pb, atomic number is 82, number of protons is 82, number of neutrons is 125, number of electrons is 82, mass number is 207, and isotope notation is $^{207}_{82}\text{Pb}$.