Periodicity

Friday, December 14, 2012

Due Monday: Alternate Universe Chemistry Worksheet and the Metal Reactivity Lab. The test is on Tuesday.

Today in class we learned everything there is to know about Periodicity. Mr. Lieberman showed us a couple of videos about how the Alkali Metals react with water. Then he showed us his own demonstration of how Aluminum and Magnesium react with air through a flame.  Aluminum had nearly no reaction and Magnesium had a vigorous reaction.  After this, we conducted our own lab to discover some periodic trends involving the reactivity of metals.

Reaction with Aluminum








Reaction with Magnesium

These were the results from my lab.  We tested reactivity of the metals: Calcium, Aluminum, and Magnesium with water and with Hydrochloric Acid.  We saw that Calcium was the most reactive in both cases.  We saw that Magnesium had a slight reaction with the two solutions.  We could not detect a reaction with the Aluminum in either of the solutions.  With this information, we could deduct certain information pertaining to periodic trends. We could clearly see that as you move across the periodic table, from left to right, reactivity decreases. (Magnesium more reactive than Aluminum.  We could also see that as you move down a column of the Periodic Table,  reactivity increases. (Calcium greater reaction than Magnesium)




Reactivity decreases for metals as you move across a row because it becomes harder for them them to lose electrons.  It increases as you move down a row because it becomes easier to lose an electron. We saw this in the videos we watched with the Alkali Metals. The reactions kept getting bigger and bigger all the way until Cesium's reaction with water made the bathtub explode.

The next scribe will be... JANE B