It should have 10 electrons
Isotope- variation of an element
Sixteen- atomic number of oxygen
The Triassic period is one of the geological periods and is the shortest of the Mesozoic era. Cambrian is the older era than the Triassic period.
<h3>What is Cambrian and triassic period?</h3>
The Triassic period existed 250 -200 million years ago and started after the vastest and most extreme devastation ever. It is the 1st period of the Mesozoic and is known for the movement of the Dinosaurs on the land, flying pterosaurs and swimming plesiosaurs and ichthyosaurs.
The Cambrian is the period of the Paleozoic era and is the most important period because of the appearance of many animals. In this period, the temperature raised on the planet and the ice sheets melted at a very dangerous rate leading to mass devastation.
Therefore, option A. <u>Cambrian</u> is older than the Triassic period.
Learn more about Cambrian and Triassic periods here:
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