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

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Multiple Choice

Which of the following is the correct molecular orbital (MO) electron configuration for Be$_2^+$?

(ext{σ}_{1s})^2 (ext{σ}^*_{1s})^2 (ext{σ}_{2s})^2

(ext{σ}_{1s})^2 (ext{σ}^*_{1s})^2 (ext{σ}_{2s})^1

(ext{σ}_{1s})^2 (ext{σ}^*_{1s})^2 (ext{σ}_{2s})^2 (ext{σ}^*_{2s})^1

(ext{σ}_{1s})^2 (ext{σ}^*_{1s})^2 (ext{σ}_{2s})^1 (ext{σ}^*_{2s})^2

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Verified step by step guidance

Determine the total number of electrons in the Be$_2^+$ ion. Since each beryllium atom has 4 electrons, Be$_2$ has 8 electrons, and removing one electron for the positive charge gives 7 electrons total.

Write down the molecular orbitals for the second period homonuclear diatomic molecules starting from the lowest energy: $\left(\text{\textbackslash sigma}_{1s}\right)$, $\left(\text{\textbackslash sigma}^*_{1s}\right)$, $\left(\text{\textbackslash sigma}_{2s}\right)$, and $\left(\text{\textbackslash sigma}^*_{2s}\right)$.

Fill the molecular orbitals with the 7 electrons following the Aufbau principle (fill lower energy orbitals first), Pauli exclusion principle (max 2 electrons per orbital with opposite spins), and Hund's rule (maximize unpaired electrons in degenerate orbitals).

Count the electrons in each orbital as you fill them: first fill $\left(\text{\textbackslash sigma}_{1s}\right)^2$, then $\left(\text{\textbackslash sigma}^*_{1s}\right)^2$, then $\left(\text{\textbackslash sigma}_{2s}\right)^2$, and finally place the remaining electron in $\left(\text{\textbackslash sigma}^*_{2s}\right)$.

Compare the electron configuration you obtained with the given options to identify the correct molecular orbital electron configuration for Be$_2^+$.