Isobars are atoms of different elements that have the same mass number (total number of protons and neutrons), while isotones are atoms of different elements that have the same number of neutrons.
Isobars Explained
Isobars are nuclides (atomic nuclei) that share the same mass number (A), which is the sum of protons (Z) and neutrons (N). However, they have different atomic numbers (Z), meaning they are different chemical elements. Since they are different elements, they exhibit different chemical properties.
- Key Feature: Same mass number (A = Z + N), different atomic number (Z)
- Elements: Different chemical elements
- Chemical Properties: Different
Example:
Consider two isobars: Carbon-14 (14C) and Nitrogen-14 (14N).
- 14C has 6 protons and 8 neutrons (A = 14).
- 14N has 7 protons and 7 neutrons (A = 14).
Despite having the same mass number (14), they are different elements because they have different numbers of protons.
Isotones Explained
Isotones are nuclides of different chemical elements that have the same number of neutrons (N). Because they are different elements, they will have different numbers of protons (Z) and, consequently, different mass numbers (A).
- Key Feature: Same number of neutrons (N), different atomic number (Z)
- Elements: Different chemical elements
- Chemical Properties: Different
- Mass number (A): Different
Example:
Consider two isotones: Silicon-30 (30Si) and Phosphorus-31 (31P).
- 30Si has 14 protons and 16 neutrons.
- 31P has 15 protons and 16 neutrons.
Both have 16 neutrons, making them isotones, but they are different elements and have different mass numbers.
Summary Table
| Feature | Isobars | Isotones |
|---|---|---|
| Mass Number (A) | Same | Different |
| Atomic Number (Z) | Different | Different |
| Neutron Number (N) | Different | Same |
| Chemical Element | Different | Different |
In conclusion, isobars are atoms of different elements with the same mass number, while isotones are atoms of different elements with the same number of neutrons.
