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

Valence Electrons of Elements

General Chemistry

10. Periodic Properties of the Elements

Valence Electrons of Elements

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Multiple Choice

Which pair of elements has the same number of valence electrons?

Mg and Al

Na and K

O and Cl

C and N

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Recall that valence electrons are the electrons in the outermost shell of an atom and determine the chemical properties of the element.

Identify the group number of each element in the periodic table, as elements in the same group have the same number of valence electrons.

For Mg (magnesium) and Al (aluminum): Mg is in group 2, so it has 2 valence electrons; Al is in group 13, so it has 3 valence electrons. They do not have the same number of valence electrons.

For Na (sodium) and K (potassium): Both are in group 1, so each has 1 valence electron. This pair has the same number of valence electrons.

For O (oxygen) and Cl (chlorine): O is in group 16 with 6 valence electrons; Cl is in group 17 with 7 valence electrons. For C (carbon) and N (nitrogen): C is in group 14 with 4 valence electrons; N is in group 15 with 5 valence electrons. Neither pair has the same number of valence electrons.