Periodic Table Assignment
1. Which is the element with the greatest density? What is that density?
2. What is the element with the lowest boiling point? For what range of temperatures could that element remain as liquid?
3. What is an allotrope? Provide the names for two allotropes of carbon.
4. The element that accounts for nearly half of the mass of the earth’s crust and two thirds of the mass of the human body was at one point referred to as “dephlogisticated air” or “fire air”. Answer the following:
a) What does it mean to dephlogisticate air?
b) What element is this?
c) Give the technological use for this element.
d) Give a biological use for this element (other than the fact that it makes up two thirds of you body mass.)
e) All allotrope of this element is extremely toxic (an hours exposure to as little as 50 ppm is likely fatal to most humans) so why are we so worried about this allotrope disappearing?
5. Name 3 isotopes of hydrogen. Give their atomic numbers and atomic masses (in amu). Bonus for describing what an amu is and why we use carbon as the bases for this definition.
6. Which of the gaseous elements would be detectable by smell or sight? (you should find 3)
7. Who discovered the element rhenium?
8. Which noble gas is the least “noble”? (ie. reacts with other stuff.)
9. What contribution did Henry Moseley (1913) make to our model of the atom?
10. For the element selenium answer the following:
a) How many protons and neutrons does an atom of selenium have?
b) Give the electron shell configuration for an atom of selenium.
c) What are the 3 technological uses for selenium?
d) Why is selenium essential to human health? Where do we get our dietary selenium from? How much dietary selenium do we need each day?