Answer:
Rb: [Kr] 5s
Step-by-step explanation:
Rb is element 37, the first element in Period 5.
It has one valence electron, so its valence electron configuration is 5s.
The noble gas configuration uses the symbol of the previous noble gas as a shortcut for the electron configurations of the inner electrons.
The preceding noble gas is Kr, so the electron configuration is Rb: [Kr] 5s.
The observation in the illustration remains in accordance with the law of conservation of mass assuming that moisture is present in the container.
<h3>What is the law of conservation of mass?</h3>The law state that mass can neither be created nor destroyed. However, mass can be converted from one form to another.
In this case, the ion was placed in a container of pure oxygen. Assuming that moisture is present, iron reacts with oxygen to form rust according to the following equation:
The rust formed will weigh more than the initial weight of the iron.
Without the presence of moisture, one can effectively conclude that the observation violates the law of conservation of mass.
More on the law of conservation of mass can be found here: brainly.com/question/13383562
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