Aufbau Principle quiz

More questions about Aufbau Principle

These visible examples show the question style. LearnClash turns the full topic into ranked duels and spaced repetition.

1. 1 Easy

   How many total electrons fit into a single d-subshell?

   Answer: Ten

   Why: Five orbitals hold two electrons each, and that arithmetic is why the corresponding block of the periodic table is ten columns wide.

2. 2 Medium

   Which shiny metal breaks the standard Aufbau filling order?

   Answer: Chromium

   Why: It ends up with a half-filled d-subshell and a single s electron, an arrangement that turns out to sit lower in energy.

3. 3 Hard

   Why do transition metals like Molybdenum deviate from Aufbau rules?

   Answer: half-filled d-subshells

   Why: The element one row up does exactly the same, yet tungsten directly below keeps the textbook arrangement, so the shortcut is a tendency and not a rule.

4. 4 Easy

   Which scientist named "Aufbau" is the principle named after?

   Answer: There is no Dr. Aufbau

   Why: The word is an ordinary German noun rather than anyone at all, and the principle itself is usually credited to Niels Bohr in the early 1920s.

5. 5 Medium

   Which mathematical rule determines the order of the Aufbau principle?

   Answer: $n + l$ rule

   Why: It is also called the Madelung rule, and where two subshells tie, the one with the smaller principal number fills first.

6. 6 Hard

   Which element's ground state configuration ends in $4d^{10} 5s^0$?

   Answer: Palladium

   Why: Palladium fills 4d completely instead of 5s2 4d8, making it the heaviest element with only one incomplete electron shell.