Question

homework- protons, neutrons, elements pra... / king foster - subatomic partic...
table with columns: name of element, element symbol, mass number, atomic number, protons, neutrons, electrons. rows:

• boron: b, 11, 5, 5, 6, 5
• sodium: na, 23, 11, 11, 12, 11
• yttrium: y, 89, 39, 39, 50, 39
• copper: cu, 64, 29, (blank), 35, (blank)
• technetium: tc, 98, 43, 43, (blank), (blank)
• lead: pb, 207, 82, (blank), (blank), (blank)
• thallium: ti, 204, 81, 123, 81, (blank)
• hydrogen: h, 1, 1, 1, 0, 1
• carbon: c, 12, 6, 6, 6, 6
• nitrogen: n, 14, 7, 7, 7, 7
• barium: ba, 137, 56, 56, 81, 56
• calcium: ca, 40, 20, 20, 20, 20
• silicon: si, 28, 14, 14, 14, 14
• argon: ar, 40, 18, 18, 22, 18
• magnesium: mg, 24, 12, 12, 12, 12

Explanation:

To solve for the missing values (Protons, Neutrons, Electrons) in the table, we use the following relationships:

• Protons = Atomic Number (by definition of atomic number).
• Neutrons = Mass Number − Atomic Number (since mass number is protons + neutrons).
• Electrons = Protons (for neutral atoms, electrons equal protons).

1. Copper (Cu)

• Protons: Atomic Number = 29
• Neutrons: Mass Number − Atomic Number = \( 64 - 29 = 35 \) (already given, confirms consistency)
• Electrons: Protons = 29

2. Technetium (Tc)

• Protons: Atomic Number = 43 (already given)
• Neutrons: Mass Number − Atomic Number = \( 98 - 43 = 55 \)
• Electrons: Protons = 43

3. Lead (Pb)

• Protons: Atomic Number = 82
• Neutrons: Mass Number − Atomic Number = \( 207 - 82 = 125 \)
• Electrons: Protons = 82

4. Thallium (Ti)

There is an error here:

• Protons should equal Atomic Number (81), but 123 is incorrect.
• Neutrons should be \( \text{Mass Number} - \text{Atomic Number} = 204 - 81 = 123 \) (so the 123 was mislabeled as “Protons”; it should be Neutrons).
• Electrons: Protons = 81

Filled Table (Key Corrections/Completions):

Name of Element	Element Symbol	Mass Number	Atomic Number	Protons	Neutrons	Electrons
Technetium	Tc	98	43	43	55	43
Lead	Pb	207	82	82	125	82
Thallium	Ti	204	81	81	123	81

(Note: Thallium’s “Protons” column had a typo; the 123 belongs in Neutrons.)

Answer:

To solve for the missing values (Protons, Neutrons, Electrons) in the table, we use the following relationships:

• Protons = Atomic Number (by definition of atomic number).
• Neutrons = Mass Number − Atomic Number (since mass number is protons + neutrons).
• Electrons = Protons (for neutral atoms, electrons equal protons).

1. Copper (Cu)

• Protons: Atomic Number = 29
• Neutrons: Mass Number − Atomic Number = \( 64 - 29 = 35 \) (already given, confirms consistency)
• Electrons: Protons = 29

2. Technetium (Tc)

• Protons: Atomic Number = 43 (already given)
• Neutrons: Mass Number − Atomic Number = \( 98 - 43 = 55 \)
• Electrons: Protons = 43

3. Lead (Pb)

• Protons: Atomic Number = 82
• Neutrons: Mass Number − Atomic Number = \( 207 - 82 = 125 \)
• Electrons: Protons = 82

4. Thallium (Ti)

There is an error here:

• Protons should equal Atomic Number (81), but 123 is incorrect.
• Neutrons should be \( \text{Mass Number} - \text{Atomic Number} = 204 - 81 = 123 \) (so the 123 was mislabeled as “Protons”; it should be Neutrons).
• Electrons: Protons = 81

Filled Table (Key Corrections/Completions):

Name of Element	Element Symbol	Mass Number	Atomic Number	Protons	Neutrons	Electrons
Technetium	Tc	98	43	43	55	43
Lead	Pb	207	82	82	125	82
Thallium	Ti	204	81	81	123	81

(Note: Thallium’s “Protons” column had a typo; the 123 belongs in Neutrons.)