Explain why the hydride ion, H^-, has a noble gas configuration.

Verified step by step guidance

1. Understand the concept of a noble gas configuration: A noble gas configuration refers to the electron arrangement of noble gases, which have completely filled outer electron shells, making them stable.
2. Recall the electron configuration of a hydrogen atom: A neutral hydrogen atom has one proton and one electron, with an electron configuration of 1s¹.
3. Analyze the hydride ion (H⁻): The hydride ion is formed when a hydrogen atom gains one additional electron, resulting in a total of two electrons.
4. Determine the electron configuration of H⁻: With two electrons, the electron configuration of H⁻ becomes 1s², which is the same as the electron configuration of helium, a noble gas.
5. Conclude why H⁻ has a noble gas configuration: The hydride ion achieves a stable, fully filled 1s orbital, identical to the electron configuration of helium, thus giving it a noble gas configuration.

Key Concepts

Hydride Ion (H-)

The hydride ion (H-) is formed when a hydrogen atom gains an extra electron, resulting in a negatively charged ion. This process occurs because hydrogen, with one electron, seeks to achieve a more stable electronic configuration. The addition of an electron allows it to mimic the electron configuration of the nearest noble gas, helium.

Noble Gas Configuration

Noble gas configuration refers to the electron arrangement of noble gases, which are characterized by having full outer electron shells. This full shell configuration makes noble gases highly stable and unreactive. For hydrogen, achieving a noble gas configuration means having two electrons in its outer shell, similar to helium, which is the closest noble gas.

Electron Configuration

Electron configuration describes the distribution of electrons in an atom's orbitals. For hydrogen, the electron configuration is 1s¹, indicating one electron in the first shell. When it gains an electron to form H-, its configuration becomes 1s², which matches the stable configuration of helium, thus explaining why H- is considered to have a noble gas configuration.