Question: How many atoms of a chlorine element would be needed to react with one atom of helium?
Answer: <u>So... for the element of CHLORINE, you already know that the atomic number tells you the number of electrons. That means there are 17 electrons in a chlorine atom. Looking at the picture, you can see there are two electrons in shell one, eight in shell two, and seven in shell three.</u>
Since each data contain 3 significant digits, the answer must be reported with 3 significant digits. So, the correct answer is 0.0409 M, which is the option B.
