Free Printable Electron Configuration Orbital Diagram Worksheets - Free Printable

Let's solve each part of this worksheet step by step.

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1. Write the long-form electron configuration of the following elements

Long-form electron configuration means writing out all orbitals in order, starting from 1s, up to the highest energy level occupied.

#### i. Lithium (Li)
- Atomic number: 3
- Electrons: 3
- Order: 1s → 2s → 2p
- Configuration: 1s² 2s¹

#### ii. Magnesium (Mg)
- Atomic number: 12
- Electrons: 12
- Configuration: 1s² 2s² 2p⁶ 3s²

#### iii. Potassium (K)
- Atomic number: 19
- Electrons: 19
- Configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹

> Note: After 3p⁶, the next orbital is 4s before 3d.

#### iv. Nickel (Ni)
- Atomic number: 28
- Electrons: 28
- Configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁸

> Note: The 4s fills before 3d, but in writing configurations, we list in order of increasing n (principal quantum number), so 3d comes after 4s.

#### v. Bromine (Br)
- Atomic number: 35
- Electrons: 35
- Configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁵

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2. Write the abbreviated electron configuration of the following elements

Abbreviated configuration uses the noble gas core preceding the element.

#### i. Nitrogen (N)
- Atomic number: 7
- Noble gas before N: He (atomic number 2)
- Remaining electrons: 5 → 2s² 2p³
- Abbreviated: [He] 2s² 2p³

#### ii. Argon (Ar)
- Atomic number: 18
- It is a noble gas itself, so its configuration is just: [Ar]
- But if you want to write it as an abbreviation for itself: [Ar]

> Or more fully: [Ne] 3s² 3p⁶ — but since it's Ar, we usually just say [Ar]

#### iii. Manganese (Mn)
- Atomic number: 25
- Noble gas before Mn: Ar (18)
- Remaining: 7 electrons → 4s² 3d⁵
- Abbreviated: [Ar] 4s² 3d⁵

#### iv. Silver (Ag)
- Atomic number: 47
- Noble gas before Ag: Kr (36)
- Remaining: 11 electrons
- Expected: [Kr] 5s² 4d⁹ — BUT silver has an exception: it’s more stable with a full d-subshell
- Actual: [Kr] 5s¹ 4d¹⁰

> This is an exception due to stability of filled d-orbital.

#### v. Barium (Ba)
- Atomic number: 56
- Noble gas before Ba: Xe (54)
- Remaining: 2 electrons → 6s²
- Abbreviated: [Xe] 6s²

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3. Identify the elements from the orbital filling diagrams

We’ll count total electrons based on arrows (each arrow = one electron).

#### Diagram 1:
```
1s ↑↓ 2s ↑↓ 2p ↑↓ ↑ ↑
1s 2s 2p
```
- 1s: 2 e⁻
- 2s: 2 e⁻
- 2p: 4 e⁻ (two paired, two unpaired → 2 + 2 = 4)
- Total: 2 + 2 + 4 = 8 electrons
- Element with atomic number 8: Oxygen (O)

> Check: O has configuration: 1s² 2s² 2p⁴ → matches

✔ Answer: Oxygen

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#### Diagram 2:
```
1s ↑↓ 2s ↑↓ 2p ↑↓ ↑↓ ↑↓ 3s ↑↓ 3p ↑↓ ↑↓ ↑
1s 2s 2p 3s 3p
```
- 1s: 2
- 2s: 2
- 2p: 6
- 3s: 2
- 3p: 5 (three boxes: two pairs and one single → 4 + 1 = 5)
- Total: 2+2+6+2+5 = 17 electrons
- Element: Chlorine (Cl)

✔ Answer: Chlorine

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#### Diagram 3:
```
1s ↑↓ 2s ↑↓ 2p ↑↓ ↑↓ ↑↓ 3s ↑↓ 3p ↑↓ ↑↓ ↑↓ 4s ↑
1s 2s 2p 3s 3p 4s
```
- 1s: 2
- 2s: 2
- 2p: 6
- 3s: 2
- 3p: 6
- 4s: 1
- Total: 2+2+6+2+6+1 = 19 electrons
- Element: Potassium (K)

✔ Answer: Potassium

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#### Diagram 4:
```
1s ↑↓ 2s ↑↓ 2p ↑↓ ↑↓ ↑↓ 3s ↑↓ 3p ↑↓ ↑↓ ↑↓ 4s ↑↓ 3d ↑ ↑ ↑ ↑ ↑
1s 2s 2p 3s 3p 4s 3d
```
- 1s: 2
- 2s: 2
- 2p: 6
- 3s: 2
- 3p: 6
- 4s: 2
- 3d: 5 (five unpaired electrons → 5 e⁻)
- Total: 2+2+6+2+6+2+5 = 25 electrons
- Element: Manganese (Mn)

✔ Answer: Manganese

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#### Diagram 5:
```
1s ↑↓ 2s ↑↓ 2p ↑↓ ↑↓ ↑↓ 3s ↑↓ 3p ↑↓ ↑↓ ↑↓ 4s ↑↓ 3d ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ 4p ↑ ↑ ↑
1s 2s 2p 3s 3p 4s 3d 4p
```
- 1s: 2
- 2s: 2
- 2p: 6
- 3s: 2
- 3p: 6
- 4s: 2
- 3d: 10 (all paired → 10 e⁻)
- 4p: 3 (three unpaired → 3 e⁻)
- Total: 2+2+6+2+6+2+10+3 = 39 electrons

Wait — that’s 39, but let’s double-check:

- Up to 3p: 18 e⁻ (same as Ar)
- 4s: 2 → 20
- 3d: 10 → 30
- 4p: 3 → 33

Wait! That’s 33 electrons?

Hold on: Let's recount carefully.

- 1s: 2
- 2s: 2
- 2p: 6 → total so far: 10
- 3s: 2 → 12
- 3p: 6 → 18
- 4s: 2 → 20
- 3d: 10 → 30
- 4p: 3 → 33 electrons

So atomic number 33 → Arsenic (As)

✔ Answer: Arsenic

But wait — the diagram shows:
- 4p has three boxes, each with one ↑ → so 3 electrons (unpaired)
- So yes, 4p³

And total electrons: 33 → Arsenic (As)

✔ Answer: Arsenic

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✔ Final Answers:

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1. Long-form Electron Configurations

i. Lithium: 1s² 2s¹
ii. Magnesium: 1s² 2s² 2p⁶ 3s²
iii. Potassium: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹
iv. Nickel: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁸
v. Bromine: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁵

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2. Abbreviated Electron Configurations

i. Nitrogen: [He] 2s² 2p³
ii. Argon: [Ar]
iii. Manganese: [Ar] 4s² 3d⁵
iv. Silver: [Kr] 5s¹ 4d¹⁰
v. Barium: [Xe] 6s²

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3. Elements from Orbital Diagrams

| Orbital Filling Diagram | Element |
|------------------------|--------|
| 1s² 2s² 2p⁴ | Oxygen |
| 1s² 2s² 2p⁶ 3s² 3p⁵ | Chlorine |
| 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹ | Potassium |
| 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁵ | Manganese |
| 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p³ | Arsenic |

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