Table of contents

1. Intro to General Chemistry3h 48m
2. Atoms & Elements4h 16m
3. Chemical Reactions4h 10m
4. BONUS: Lab Techniques and Procedures1h 38m
5. BONUS: Mathematical Operations and Functions48m
6. Chemical Quantities & Aqueous Reactions3h 53m
7. Gases3h 49m
8. Thermochemistry2h 37m
9. Quantum Mechanics2h 58m
10. Periodic Properties of the Elements3h 9m
11. Bonding & Molecular Structure3h 29m
12. Molecular Shapes & Valence Bond Theory1h 57m
13. Liquids, Solids & Intermolecular Forces2h 23m
14. Solutions3h 1m
15. Chemical Kinetics2h 53m
16. Chemical Equilibrium2h 29m
17. Acid and Base Equilibrium5h 1m
18. Aqueous Equilibrium4h 47m
19. Chemical Thermodynamics1h 50m
20. Electrochemistry2h 42m
21. Nuclear Chemistry2h 36m
22. Organic Chemistry5h 7m
23. Chemistry of the Nonmetals2h 39m
24. Transition Metals and Coordination Compounds3h 16m

10. Periodic Properties of the Elements

The Electron Configuration

General Chemistry

10. Periodic Properties of the Elements

The Electron Configuration

Previous problemNext problem

Struggling with General Chemistry?

Join thousands of students who trust us to help them ace their exams!Watch the first video

Multiple Choice

Which of the following elements has an electron configuration of [Kr] 5s^2?

Strontium

Rubidium

Calcium

Barium

Previous problemNext problem

Verified step by step guidance

Step 1: Understand the notation [Kr] 5s^2. The symbol [Kr] represents the electron configuration of the noble gas krypton, which is a shorthand for the inner electrons. The configuration 5s^2 means there are two electrons in the 5s orbital beyond krypton's configuration.

Step 2: Recall the position of krypton (Kr) in the periodic table. Krypton has an atomic number of 36, so the next elements after krypton will start filling the 5s orbital.

Step 3: Identify the elements that come after krypton and their electron configurations. The element with configuration [Kr] 5s^1 is rubidium (Rb), and the element with configuration [Kr] 5s^2 is strontium (Sr).

Step 4: Compare the given options: Rubidium (Rb), Calcium (Ca), Barium (Ba), and Strontium (Sr). Calcium has the configuration [Ar] 4s^2, which is before krypton, and barium has the configuration [Xe] 6s^2, which is after strontium.

Step 5: Conclude that the element with the electron configuration [Kr] 5s^2 is strontium (Sr), as it directly follows krypton and has two electrons in the 5s orbital.