How are the elements arranged on the periodic table?

They are arranged by increasing atomic mass/number. Atomic mass/number is identified by the amount of protons in the element. For example, Helium has an atomic mass of 2. That means it has 2 protons. Groups are identified when elements have similar properties, and periods are the rows of elements with the same number of electron shells.

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organisms are more likely to be more preserved in mud than sand because mud is moist and wet, while sand is very dry.