Mini-Quiz: Chemical Elements

1. What does the atomic number designate?

   An alphabetical rankingSorry, not correct. Try another button. The number of protons in the nucleusThat is correct. You look like an upcoming Champion. The number of protons and neutrons in the nucleusGood try, but not right. Select another answer.

2. If the average atomic weight of atomic number 11 (Sodium) is 22.989770, how many neutrons are in its most common isotope?

   Round off 22.989770 to get 23 and add 11 to get 34Sorry, not correct. Try another button. Round off 22.989770 to get 23 and subtract 11 to get 12Correct. It is quite elementary. Round off 22.989770 to get 22 and divide by 11 to get 2Oops! Wrong answer. Re-read the question and try again.

3. Why are the atomic weights of the unstable elements whole numbers?

   It is just an approximation, because measurements could not be madeThat is correct. You look like an upcoming Champion. They are the few elements with an exact atomic weightGood try, but not right. Select another answer. They are so unstable that the decimals simply fell offSorry, not correct. Try another button.

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