In modern blimps, the gas of choice is used to inflate them is helium is safer. Compare and contrast the atomic structure
of hydrogen and helium. What characteristics of the atomic structure of helium make it so much less reactive than hydrogen?
The valence shell of helium is full making it less reactive, whereas hydrogen needs an electron to fill its valence shell.
Hydrogen and helium are both chemical elements, but they differ in terms of their atomic structures.
1. Atomic Structure of Hydrogen:
- Hydrogen has an atomic number of 1, indicating that it has one proton in its nucleus.
- The most common isotope of hydrogen, known as protium, contains one proton and no neutrons.
- It has one electron, which orbits around the nucleus in the first energy level.
- Hydrogen has a simple atomic structure, consisting of a single proton and electron.
2. Atomic Structure of Helium:
- Helium has an atomic number of 2, indicating that it has two protons in its nucleus.
- The most common isotope of helium, known as helium-4, contains two protons and two neutrons.
- It has two electrons, which occupy the first energy level and form a stable electron configuration.
- Helium has a filled electron configuration, meaning its outer energy level is completely filled.
Now, let's discuss the characteristics of helium's atomic structure that make it less reactive than hydrogen:
1. Electron Configuration:
- Helium's electron configuration (1s²) is stable and completely filled with two electrons in the first energy level. This stability reduces its reactivity.
- Hydrogen has only one electron in its outermost energy level, making it more reactive as it seeks another electron to attain a stable configuration.
2. Nuclear Charge:
- Helium's nucleus contains two protons, which exert a stronger positive charge compared to hydrogen's single proton.
- This stronger charge in helium's nucleus attracts its electrons more strongly, contributing to greater stability and lower reactivity.
3. Ionization Energy:
- Ionization energy refers to the energy required to remove an electron from an atom in its gaseous state.
- Helium has a higher ionization energy compared to hydrogen. It is more difficult to remove an electron from helium due to its stable electron configuration, making it less reactive.
Overall, the atomic structure of helium, including its stable electron configuration, stronger nuclear charge, and higher ionization energy, make it less reactive than hydrogen.
To compare and contrast the atomic structure of hydrogen (H) and helium (He), let's start with the basics.
Hydrogen:
- Atomic number: 1
- Atomic mass: 1.00784 atomic mass units (AMU)
- Electron configuration: 1s1
Helium:
- Atomic number: 2
- Atomic mass: 4.0026 AMU
- Electron configuration: 1s2
Now, let's explore the characteristics of the atomic structure that make helium much less reactive than hydrogen:
1. Electrons: Both hydrogen and helium have only one electron in their outermost shell. However, in the case of helium, it has a completely filled outermost shell, containing two electrons, which gives it a more stable electron configuration. On the other hand, hydrogen has just one electron in its outermost shell, making it more likely to interact with other atoms to achieve a stable electron configuration.
2. Electron affinity: Helium has lower electron affinity compared to hydrogen. Electron affinity refers to the energy change that occurs when an atom gains an electron. Since helium already has a stable electron configuration, it has little tendency to gain an additional electron, making it less likely to react with other elements. Hydrogen, on the other hand, has a greater tendency to gain an electron to achieve a stable configuration. This higher electron affinity increases its reactivity.
3. Ionization energy: Ionization energy is the energy required to remove an electron from an atom. Helium has a higher ionization energy compared to hydrogen. Its full outer shell makes it more difficult to remove an electron. In contrast, hydrogen has a lower ionization energy since removing its single outer electron requires less energy. This lower ionization energy makes hydrogen more reactive, as it readily donates its electron to other atoms.
4. Nuclear charge: Helium's atomic nucleus contains two protons, whereas hydrogen's atomic nucleus contains only one proton. The nuclear charge in helium is higher than hydrogen, resulting in stronger attractive forces between the nucleus and electrons. This increased nuclear charge leads to a greater stability, reducing the likelihood of reacting with other atoms.
In summary, helium's atomic structure with a full outer shell, low electron affinity, higher ionization energy, and stronger nuclear charge contribute to its inert nature. These factors make helium much less reactive than hydrogen, which is more likely to undergo chemical reactions to gain stability.