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Electron Configurations and Orbital Diagrams

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Objectives:

In this lesson we will go into more detail on how electrons are arranged in an atom. We will learn that:

  • energy levels have sublevels: s, p, d and f
  • each sublevel has a different type and number of orbitals where electrons are located
  • each orbital can hold 2 electrons with opposite spins

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Revising the Atomic Model

Electron Cloud Model

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Shell Model Explained

Energy shells

(n)

Number of electrons

(2n²)

Subshells

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Atomic Orbitals

Increasing Energy

Each subshell has a different type and number of orbitals.

s = 1 orbital, 2e-

p= 3 orbitals, 6e-

d = 5 orbitals, 10e-

f = 7 orbitals, 14e-

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This shows the order in which electrons will fill the different sublevels. Each box represents an orbital that can hold 2 electrons. Each sublevel will get one electron in each orbital before they start pairing up. Two electrons in the same orbital will have opposite spins.

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Electron Configurations

Atomic number

Arrows represent electrons.

Electron pair

Energy shell and subshells

Superscript gives number of electrons.

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Electron Configuration

Orbital Diagram

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Patterns in Electron Configurations

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Practice:

Draw the orbital diagram and write the electron configuration for the following elements:

  1. Carbon
  2. Sodium
  3. Cobalt
  4. Phosphorus

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Practice:

Draw the orbital diagram and write the electron configuration for the following elements:

  • Carbon
  • Sodium
  • Cobalt
  • Phosphorus

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Practice:

Draw the orbital diagram and write the electron configuration for the following elements:

  • Carbon
  • Sodium
  • Cobalt
  • Phosphorus

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Practice:

Draw the orbital diagram and write the electron configuration for the following elements:

  • Carbon
  • Sodium
  • Cobalt
  • Phosphorus

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Practice:

Draw the orbital diagram and write the electron configuration for the following elements:

  • Carbon
  • Sodium
  • Cobalt
  • Phosphorus

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Electron Configuration and Orbital Diagrams Review

Write the answers to the review slides in your notebook. Be sure to write neatly and clearly label the questions

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  1. List the 4 sublevels in order from least energy to most energy.

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2. To which block do these elements belong s, p, d or f?

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Element

Block

Zinc (Zn)

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Cesium (Cs)

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Antimony (Sb)

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Plutonium (Pu)

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Potassium (K)

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Titanium (Ti)

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Aluminum (Al)

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Californium (Cf)

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3. What is the first element to have electrons in each of the sublevels?

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Sublevel

First Element

s

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p

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d

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f

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4. Draw an orbital diagram and write the electron configuration for Antimony, Sb.

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5. Draw an orbital diagram and write the electron configuration for Iron, Fe.

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Writing short-hand configurations

Noble gases have full outer subshells.

For example, neon has the electron configuration

1s²2s²2p⁶

To write the short-hand electron configuration for sulfur, start with neon, then add sulfur’s valence electrons.

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S = [Ne]3s23p4

The electron configurations for noble gases always end in np6, because they have full outer shells.

These are also the core electrons for the elements in the next row; Na, Mg, Al, Si, P, S, Cl

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Write the short-hand electron configuration for the following elements:

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6. Barium, Ba

7. Silver, Ag

8. Tungsten, W

9. Francium, Fr

10. Uranium, U

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