Question

electrons and their arrangement in atoms
chemistry
name_________
period 1 2 3 4 5 6 date____
draw the orbital box diagram and the noble gas electron configuration of the following elements:
titanium- ti selenium- se
silver – ag molybdenum - mo

use your notes on electron configurations and atomic spectra to answer the following questions:

1. if each orbital can hold a maximum of two electrons, how many electrons can each of the following hold? a. 2s ____ b. 5p __ c. 4d ____
2. how many s orbitals can there be in an energy level?
3. how many p orbitals can there be in an energy level?
4. which is the lowest energy level that can have an s orbital?

Explanation:

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Part 1: Orbital Box Diagrams & Noble Gas Configurations

Titanium (Ti, Atomic #22)

Step1: Find noble gas core

Noble gas before Ti is Ar ($Z=18$)

Step2: Add valence electrons

Remaining electrons: $22-18=4$. Fill $4s^2$, then $3d^2$
Orbital box diagram:

[Ar]  4s: ↑↓  3d: ↑  ↑  □  □  □

Noble gas config: $[Ar] 4s^2 3d^2$

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Selenium (Se, Atomic #34)

Step1: Find noble gas core

Noble gas before Se is Ar ($Z=18$)

Step2: Add valence electrons

Remaining electrons: $34-18=16$. Fill $4s^2$, $3d^{10}$, then $4p^4$
Orbital box diagram:

[Ar]  4s: ↑↓  3d: ↑↓ ↑↓ ↑↓ ↑↓ ↑↓  4p: ↑↓ ↑  ↑  □

Noble gas config: $[Ar] 4s^2 3d^{10} 4p^4$

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Silver (Ag, Atomic #47)

Step1: Find noble gas core

Noble gas before Ag is Kr ($Z=36$)

Step2: Add valence electrons (exception)

Remaining electrons: $47-36=11$. Filled $5s^1$ (stable full d), then $4d^{10}$
Orbital box diagram:

[Kr]  5s: ↑  4d: ↑↓ ↑↓ ↑↓ ↑↓ ↑↓

Noble gas config: $[Kr] 5s^1 4d^{10}$

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Molybdenum (Mo, Atomic #42)

Step1: Find noble gas core

Noble gas before Mo is Kr ($Z=36$)

Step2: Add valence electrons (exception)

Remaining electrons: $42-36=6$. Filled $5s^1$ (stable half d), then $4d^5$
Orbital box diagram:

[Kr]  5s: ↑  4d: ↑  ↑  ↑  ↑  ↑

Noble gas config: $[Kr] 5s^1 4d^5$

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Part 2: Orbital Capacity & Count Questions

Question 1

Step1: 2s orbital capacity

s-subshell has 1 orbital; $1 \times 2 = 2$

Step2: 5p orbital capacity

p-subshell has 3 orbitals; $3 \times 2 = 6$

Step3: 4d orbital capacity

d-subshell has 5 orbitals; $5 \times 2 = 10$

Question 2

Step1: s orbital count per energy level

s-subshell only has 1 orbital per $n$

Question 3

Step1: p orbital count per energy level

p-subshell has 3 orbitals per $n \geq 2$

Question 4

Step1: Lowest energy level for s orbital

s-orbitals exist starting at $n=1$

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Answer:

Orbital Box Diagrams & Noble Gas Configurations

1. Titanium (Ti)

• Orbital Box Diagram:

      [Ar]  4s: ↑↓  3d: ↑  ↑  □  □  □

• Noble Gas Configuration: $[Ar] 4s^2 3d^2$

1. Selenium (Se)

• Orbital Box Diagram:

      [Ar]  4s: ↑↓  3d: ↑↓ ↑↓ ↑↓ ↑↓ ↑↓  4p: ↑↓ ↑  ↑  □

• Noble Gas Configuration: $[Ar] 4s^2 3d^{10} 4p^4$

1. Silver (Ag)

• Orbital Box Diagram:

      [Kr]  5s: ↑  4d: ↑↓ ↑↓ ↑↓ ↑↓ ↑↓

• Noble Gas Configuration: $[Kr] 5s^1 4d^{10}$

1. Molybdenum (Mo)

• Orbital Box Diagram:

      [Kr]  5s: ↑  4d: ↑  ↑  ↑  ↑  ↑

• Noble Gas Configuration: $[Kr] 5s^1 4d^5$

Orbital Capacity & Count Answers

1. a. 2; b. 6; c. 10
2. 1
3. 3
4. Energy level 1 ($n=1$)