Helium is in group 18 of the periodic table. How is helium different from the other elements in this group?
Helium is different from the other elements in group 18, also known as the Noble Gases, because it has only two electrons in its outermost energy level (valence electrons), while the other elements in the group have eight valence electrons. This makes helium chemically inert and less likely to form compounds with other elements. Additionally, helium has the lowest atomic number and atomic mass in the group, with a completely filled first energy level, whereas the other elements have additional energy levels.
Helium is different from the other elements in Group 18 of the periodic table, also known as the noble gases, in several ways:
1. Atomic number: Helium is the lightest element in Group 18, with an atomic number of 2. The other elements in this group have higher atomic numbers, ranging from 10 to 54.
2. Electron configuration: Helium has a unique electron configuration. It has two electrons in its outermost energy level (1s^2), making it stable and chemically unreactive. In contrast, the other elements in this group have varying numbers of electrons in their outermost energy level.
3. Physical properties: Helium is the only element in Group 18 that exists as a monatomic gas under normal conditions. It has the lowest boiling point and melting point among the noble gases. The other elements in this group have higher boiling and melting points.
4. Abundance: Helium is the second most abundant element in the universe, after hydrogen. It is produced through nuclear fusion in stars and can be found in large quantities on Earth, particularly in natural gas deposits. The other elements in Group 18 are relatively rare in comparison.
Overall, while helium shares some characteristics with the other elements in Group 18, its unique atomic number, electron configuration, physical properties, and abundance differentiate it from the rest of the noble gases.