Experience 4: Modern Atomic Theory

Experience 4: Modern Atomic Theory

by Danielle Pedroso

​Learning Objectives

• ​Investigate how the quantum mechanical nature of the electron gave rise to modern atomic orbital theory.

• Evaluate how the quantum mechanical nature of the electron can be used to refine models of the atom. 

Revising the Atomic Model

• Quantum Mechanical Model -

• Similarities to Bohr Model: energies of electrons are restricted to certain values

• ​Differences: NO EXACT PATH

  • ​Atomic Orbital is where there is a high probability of finding an electron

Multiple Choice

Which atomic model uses atomic orbitals to describe the probable location of any electron in a three-dimensional space?

• A. the cubic model

• B. the plum-pudding model

• C. the planetary model

• D. the quantum mechanical model

​Shell Model

Number of principal energy shell, n, increases further from nucleus.

​# of electrons in each energy shell = 2n²

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​Subshells: s, p, d, f

​A square represents orbitals in each subshell

​(2 electrons per square)

​Each energy shell have subshells.

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​Each subshells have number of orbitals that hold two electrons each.

Multiple Choice

The electron shell model of an atom has three main components: the energy shell, the subshell, and the orbital. Which of the following represent the correct arrangement from the lowest to highest maximum capacity to hold electrons?

• A. orbitals < energy shell < subshell

• B. energy shell < orbitals < subshell

• C. subshell < orbitals < energy shell

• D. orbitals < subshell < energy shell

Fill in the Blanks

Why does the number of electrons in each principal energy shell increase as the number of the shell increases?

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Example: Magnesium Atom

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Multiple Choice

The figure is a 3-dimensional representation of an atomic orbital. Which orbital does it represent?

• A. an s-orbital

• B. a single p-orbital

• C. three d-orbitals

• D. three p-orbitals

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​Electrons fill the lowest possible energy subshells first.

Multiple Choice

The figure shows a 3D model of the shapes of a particular element’s atomic orbitals. If all the orbitals shown in the 3D model are completely filled, how many electrons does this element have?

• 4

• 6

• 10

• 18

Multiple Choice

Choose the correct sequence of subshells represented in the diagram, in order from lowest to highest energy level.

• A. 1s > 2s > 3s

• B. 1s > 2p > 2s

• C. 1s > 2s > 2p

• D. 1s > 2s > 3s > 2p

Fill in the Blanks

List the subshells that hold the 25 electrons in a manganese atom in order of increasing energy.

Interactivity: The Quantum Mechanical Models and Atomic Orbitals

• ​Due today!