QuestenaPráctica que te muestra qué repasar después
BuscarCrear una prueba
Pregunta 75

A freshly cut alkali metal starts bright but soon becomes dull in ordinary air. What best explains this family-specific observation?

  1. The metal changes into a gas at once.
  2. Its exposed surface reacts rapidly with air.Respuesta correcta
  3. The interior permanently loses all metallic properties.
  4. Air polishes the surface into a dull layer.

Explicación

The exposed surface rapidly reacts with substances in air, creating a tarnished layer that hides the metallic shine. Permanent brightness would imply little surface reaction and contradict the quick change that was observed.

Continúa con este test

Empezar la práctica
Comprender este tema (≈5 min)Volver a la prueba
Pregunta 75: A freshly cut alkali metal starts bright but soon becomes… · The Periodic Table and Elements · Questena