Table of contents

1. A Review of General Chemistry5h 5m
2. Molecular Representations1h 14m
3. Acids and Bases2h 46m
4. Alkanes and Cycloalkanes4h 17m
5. Chirality3h 39m
6. Thermodynamics and Kinetics1h 22m
7. Substitution Reactions1h 48m
8. Elimination Reactions2h 30m
9. Alkenes and Alkynes2h 9m
10. Addition Reactions3h 19m
11. Radical Reactions1h 58m
12. Alcohols, Ethers, Epoxides and Thiols2h 42m
13. Alcohols and Carbonyl Compounds2h 17m
14. Synthetic Techniques1h 26m
15. Analytical Techniques:IR, NMR, Mass Spect7h 3m
16. Conjugated Systems6h 13m
17. Ultraviolet Spectroscopy51m
18. Aromaticity2h 34m
19. Reactions of Aromatics: EAS and Beyond5h 1m
20. Phenols55m
21. Aldehydes and Ketones: Nucleophilic Addition4h 56m
22. Carboxylic Acid Derivatives: NAS2h 51m
23. The Chemistry of Thioesters, Phophate Ester and Phosphate Anhydrides1h 10m
24. Enolate Chemistry: Reactions at the Alpha-Carbon1h 53m
25. Condensation Chemistry2h 9m
26. Amines1h 43m
27. Heterocycles2h 0m
28. Carbohydrates5h 53m
29. Amino Acids4h 20m
30. Peptides and Proteins2h 42m
31. Catalysis in Organic Reactions1h 30m
32. Lipids 2h 50m
33. The Organic Chemistry of Metabolic Pathways2h 52m
34. Nucleic Acids1h 32m
35. Transition Metals6h 14m
36. Synthetic Polymers1h 49m

1. A Review of General Chemistry

Bonding Preferences

Organic Chemistry

1. A Review of General Chemistry

Bonding Preferences

Previous problemNext problem

Problem 6c,d

Textbook Question

Look at the relative positions of each pair of atoms listed here in the periodic table. How many core electrons does each have? How many valence electrons does each have?
c. nitrogen and phosphorus
d. magnesium and calcium

Verified step by step guidance

Step 1: Recall the periodic table structure. Elements are arranged in periods (rows) and groups (columns). Core electrons are the inner electrons that are not involved in bonding, while valence electrons are the outermost electrons in the highest energy level.

Step 2: For nitrogen (N), locate it in Group 15 (or Group 5A) and Period 2. Nitrogen has an atomic number of 7, meaning it has 7 electrons. Its electron configuration is 1s² 2s² 2p³. The core electrons are those in the 1s orbital (2 electrons), and the valence electrons are in the 2s and 2p orbitals (5 electrons).

Step 3: For phosphorus (P), locate it in Group 15 (or Group 5A) and Period 3. Phosphorus has an atomic number of 15, meaning it has 15 electrons. Its electron configuration is 1s² 2s² 2p⁶ 3s² 3p³. The core electrons are those in the 1s, 2s, and 2p orbitals (10 electrons), and the valence electrons are in the 3s and 3p orbitals (5 electrons).

Step 4: For magnesium (Mg), locate it in Group 2 (or Group 2A) and Period 3. Magnesium has an atomic number of 12, meaning it has 12 electrons. Its electron configuration is 1s² 2s² 2p⁶ 3s². The core electrons are those in the 1s, 2s, and 2p orbitals (10 electrons), and the valence electrons are in the 3s orbital (2 electrons).

Step 5: For calcium (Ca), locate it in Group 2 (or Group 2A) and Period 4. Calcium has an atomic number of 20, meaning it has 20 electrons. Its electron configuration is 1s² 2s² 2p⁶ 3s² 3p⁶ 4s². The core electrons are those in the 1s, 2s, 2p, 3s, and 3p orbitals (18 electrons), and the valence electrons are in the 4s orbital (2 electrons).

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above

Play a video:

Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Core Electrons

Core electrons are the electrons that are located in the inner shells of an atom, which are not involved in chemical bonding. These electrons are typically closer to the nucleus and are shielded from the effects of external electric fields. The number of core electrons can be determined by subtracting the number of valence electrons from the total number of electrons in an atom.

Valence Electrons

Valence electrons are the electrons in the outermost shell of an atom and are crucial for determining how an atom interacts with others during chemical reactions. The number of valence electrons influences an element's reactivity, bonding behavior, and overall chemical properties. For main group elements, the number of valence electrons corresponds to the group number in the periodic table.

Periodic Table Trends

The periodic table organizes elements based on their atomic number and electron configuration, revealing trends in properties such as electronegativity, ionization energy, and atomic size. As you move down a group, core electrons increase, while valence electrons remain in the same shell, affecting the chemical behavior of elements. Understanding these trends is essential for predicting how different elements, like nitrogen and phosphorus or magnesium and calcium, will interact.

Watch next

Master What is a valence electron? with a bite sized video explanation from Johnny

Start learning