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

2. Atoms & Elements

Ions

General Chemistry

2. Atoms & Elements

Ions

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Multiple Choice

When a Mg^{2+} ion becomes a Mg atom, the radius increases because the Mg^{2+} ion:

loses two protons, decreasing the overall positive charge of the nucleus

loses two electrons, increasing electron-electron repulsion

gains two neutrons, increasing the mass and size of the atom

gains two electrons, reducing the effective nuclear charge experienced by each electron

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Verified step by step guidance

Understand the difference between a Mg^{2+} ion and a neutral Mg atom: Mg^{2+} has lost two electrons compared to the neutral Mg atom.

Recall that the radius of an ion or atom depends on the balance between the positive charge of the nucleus (protons) and the negative charge of the electrons, as well as electron-electron repulsions.

Recognize that when Mg^{2+} gains two electrons to become Mg, the number of protons remains the same, but the number of electrons increases, which increases electron-electron repulsion and reduces the effective nuclear charge felt by each electron.

Understand that this reduction in effective nuclear charge allows the electron cloud to expand, increasing the atomic radius.

Eliminate incorrect options: the ion does not lose protons or gain neutrons during this process, so changes in nuclear charge or mass are not responsible for the radius increase.