Here is your answer
B. NaCl
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In option A. Na isn't present.
In option C. there are two atoms of Na
So, option B is correct
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Answer:
The answer is true.
Explanation:
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The answer is true.
When a crust undergoes great tension, a crack opens and the oceanic crust begins to form. As the crack enlarges, the continent is splitting. Thus an oceanic crust forms. So the oceanic crust is younger than the earth's crust.
<span>A. the dog ate everyone of his play toys</span>
The electron configuration that represent an excited state for an atom of calcium is 2, 8, 7, 3.
Calcium atom has an atomic number of 20 and its electronic configuration is 2, 8, 8, 2. An atom is said to be in an excited state if it gains energy and move to an higher energy level. For the calcium atom given above, there are 20 electrons which are distributed into four shells. But in the excited state [option 3], one of the 8 electrons in the third shell gains energy and move to the fourth shell. Thus, the number of electrons in the third shell reduced by 1, while the number of electrons in the fourth shell increase by 1.