# Periodic Trends in Reactivity

```Name: _________________________________ Date: _____________ Period: _____________
Periodic Trends in Reactivity Lab
GLO’s: ____________________________________________________________________________
HOM’s: ___________________________________________________________________________
Introduction:
The structure of the periodic table is such that elements with similar properties are aligned
vertically in columns called “groups”. This leads to smoothly varying trends in properties such as
ionization energy and atomic radius as one moves both down the periodic table within a specific
group or as one moves horizontally along a given period within the table. The reactivities of the
elements also follow well-defined trends both within groups and across periods. In this
experiment, you will explore these trends in reactivity.
Elements in the periodic table are organized by increasing atomic number. As atomic
numbers increases, so does the number the electrons. Electrons, and specifically valence
electrons, are important in determining how an atom interacts with other atoms. The elements in
a group have similar properties because they have the same number of valence electrons which
are found in similar electron configurations. The elements in the periodic table are divided into
categories. This system is useful for finding a particular element and also for making predictions
about an element based on its position in the table.
Purpose: To explore the reactivity trends of metals in groups and periods of the periodic table.
Hypothesis: _____________________________________________________________________
Pre-lab Questions:
1.) What are group? __________________________________________________________
2.) What are families? _________________________________________________________
3.) In general, where are metals located on the periodic table? _______________________
4.) What are the names of three metal families? ___________________________________
5.) What element is in Group 3 and 3rd period? ____________________________________
Part 1: Trends in the Properties within Groups
1.) Place a small strip of magnesium ribbon in a test tube and cover with 5mL water. Look
closely and observe what happens. Write your observations on the table below.
2.) Place a small piece of calcium in a test tube with 5mL of water. Record your observations.
Metal
Magnesium
Calcium
Observations: Reaction in Water
Analysis:
1.) What might be the reason for the difference in behavior between magnesium and calcium
when placed in water? (Hint: Lithium, Sodium, and Potassium are also progressively more
reactive).
2.) State the trend in reactivity for the alkali metals.
Part 2: Activity Series of Some Metals in HCl
1. Obtain a small piece of each of the metals in the data table below. Place each metal in a
small separate test tube. Add a small amount of dilute HCl to the test tube, just enough to
cover the sample.
Metal
Observations: Reactions with HCl
Magnesium
Aluminum
Copper
Zinc
Analysis:
1.) List the 4 metals from your data table from most reactive to least reactive. Use data from
2.) In general, is there a relationship between the locations of metals on the Periodic Table
and their relative activity? Explain why by using location.
Use your chemistry book or another source to locate a metal activity series or a metal reactivity
series. How does your listing above compare? Account for any differences.
Part 3: Density Trends in a Group
Silicon, tin, and lead are all in the same group. The density of tin is about 7.28 g/cm3 and the
density of lead is about 11.34 g/cm3. Based on this trend, what do you estimate the density of
silicon to be?
Estimate: __________________
Determine the density of silicon. Use the water displacement technique to find the density.
Make sure that you pat the sample dry after making your measurements and before returning to
the supply table.
Density of Silicon Data
Mass of Silicon sample (g)
Volume of water before adding sample
(mL)
Volume of water after adding sample
(mL)
Volume of sample of silicon (mL)
Density of Silicon (g/mL)
Show your set up for credit
Analysis:
2.) Determine your percent error using the accepted value for silicon from your chemistry
book’s appendix. Show your formula and numbers with units for credit.
3.) When elements are organized in the periodic table, various trends appear. Describe some
of the trends that you learned about from this lab.
Conclusion:
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Reflection:
In this lab I learned about:
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But I am still confused about:
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I have a question on:
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