Exploring Atomic Orbitals in Hydrogen

• New lesson editor
• Science
• Secondary Education
• Age 13

Learning Objective

At the end of the lesson you will be able to explain how atomic orbitals of hydrogen are defined, describe the principal quantum number (n), and clarify the relationship between energy levels and sublevels.

What do you already know about atomic orbitals and quantum numbers?

Atomic Orbitals and Probability

An atomic orbital's boundary is 'fuzzy' due to electron uncertainty. Chemists define the orbital surface to enclose 90% of the electron's probability distribution. There is a 0.9 chance of finding the electron within this boundary, making it likelier close to the nucleus.

Visualising 90% Probability Boundary

The boundary drawn for a hydrogen orbital encloses the region where the electron is most likely found. The circle commonly shown depicts this 90% probability area.

Principal Quantum Number (n)

The quantum mechanical model assigns four quantum numbers to orbitals. The principal quantum number, n, shows an orbital's relative size and energy. Increasing n means a larger orbital, an electron farther from the nucleus, and higher energy. Hydrogen's electron is in the ground state when n = 1.

Principal Energy Levels in Hydrogen

Hydrogen atoms have principal energy levels numbered 1 to 7, with n = 1 as the lowest. These levels determine the main energy regions for the electron.

Energy Levels and Sublevels

Each principal energy level (n) is like a row in a theatre—further from the stage means higher energy and more seats.

Principal Energy Levels

Energy Sublevels

Principal energy level 1 has one sublevel. Level 2 has two sublevels, and so on. The number of sublevels increases as n increases.

Analogy: The Theatre Model

Imagine rows in a theatre. Like seats increasing with each row, each higher principal energy level has more sublevels, just like how more seats fit as the rows go back.

Review: How Are Orbitals Organised?

Energy levels (n = 1 to 7) each contain sublevels—matching n in number. Orbitals within these sublevels define where electrons are likely found. The structure explains chemical behaviour and electron arrangement.

With each higher energy level, the electrons are

A

Alower in energy

B

more stable

C

weaker

D

farther from the nucleus

If n = 3, what is the maximum number of electrons that can fit in this shell?

A

9

B

6

C

18

D

3

How many electrons can P orbitals hold?

A

2 electrons

B

8 electrons

C

6 electrons

D

4 electrons

Which orbital has the highest energy level?

A

S orbitals

B

D orbitals

C

P orbitals

D

F orbitals

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