Table of contents

1. Matter and Measurements4h 31m
2. Atoms and the Periodic Table5h 23m
3. Ionic Compounds2h 18m
4. Molecular Compounds2h 18m
5. Classification & Balancing of Chemical Reactions3h 17m
6. Chemical Reactions & Quantities2h 27m
7. Energy, Rate and Equilibrium3h 46m
8. Gases, Liquids and Solids3h 25m
9. Solutions4h 10m
10. Acids and Bases3h 29m
11. Nuclear Chemistry56m
BONUS: Lab Techniques and Procedures1h 38m
BONUS: Mathematical Operations and Functions47m
12. Introduction to Organic Chemistry1h 34m
13. Alkenes, Alkynes, and Aromatic Compounds2h 12m
14. Compounds with Oxygen or Sulfur1h 6m
15. Aldehydes and Ketones1h 1m
16. Carboxylic Acids and Their Derivatives1h 11m
17. Amines39m
18. Amino Acids and Proteins1h 51m
19. Enzymes1h 37m
20. Carbohydrates1h 41m
21. The Generation of Biochemical Energy2h 8m
22. Carbohydrate Metabolism2h 22m
23. Lipids2h 26m
24. Lipid Metabolism1h 45m
25. Protein and Amino Acid Metabolism1h 37m
26. Nucleic Acids and Protein Synthesis2h 54m

2. Atoms and the Periodic Table

Ions (Simplified)

GOB Chemistry

2. Atoms and the Periodic Table

Ions (Simplified)

Previous problemNext problem

Struggling with GOB Chemistry?

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

Multiple Choice

In which pair are the two species both isoelectronic and isotopic?

Previous problemNext problem

Verified step by step guidance

Understand the definitions: Isoelectronic species have the same number of electrons, while isotopic species have the same number of protons but different numbers of neutrons.

Analyze the first pair: 40Ca^{2+} and 40Ar. Calcium ion (Ca^{2+}) has lost 2 electrons, so it has 18 electrons, which is the same as Argon (Ar). Both have the same mass number, 40, indicating they are isotopic.

Analyze the second pair: 23Na^{+} and 24Na^{+}. Both sodium ions have lost 1 electron, so they each have 10 electrons. However, they have different mass numbers (23 and 24), so they are not isotopic.

Analyze the third pair: 24Mg^{2+} and 25Mg. Magnesium ion (Mg^{2+}) has lost 2 electrons, so it has 10 electrons, while neutral magnesium (Mg) has 12 electrons. They are not isoelectronic, but they are isotopic as they have the same number of protons.

Analyze the fourth pair: 56Fe^{2+} and 57Fe^{3+}. Fe^{2+} has 24 electrons and Fe^{3+} has 23 electrons, so they are not isoelectronic. They are isotopic as they have the same number of protons but different mass numbers.