Experiment 2: The Alkaline Earths And Halogens Flashcards
As you have already seen, the elements in a given _____ in the periodic table are referred too as a _____, or a _____.
Column-Group-Family
We will be focusing on the reactivities of the following two groups in this experiment:
Alkaline Earth Metals-Halogens
Which group are the earth metals and which group are the Alkaline Earth Metals?
1A are the Earth Metals and 2A are the Alkaline Earth Metals
Between the alkali metals and the alkaline earth metals, which group is more reactive?
Alkali Metals
What properties do the Alkaline Earth Metals have?
They are highly electro positive and constitute the second most reactive group of metals. The alkaline earth metals have a larger nuclear charge than the alkali metals. Because of the larger nuclear charge, each alkaline earth metal has a smaller atomic radius than the alkali metals.
The _____ ion is an exceptionally small cation.
Beryllium
Why do Alkaline Earth Metals have a higher density, boiling point, melting point, and hardness compared too alkali metals?
Because they are smaller and have two valence electrons instead of one.
What is the trend with degree of hardness and atomic number?
With an increasing atomic number (number of protons), the degree of hardness decreases. THEY HAVE AN INVERSE RELATIONSHIP
Generally speaking, are Alkali Metals more soluble in water or Alkaline Earth Metals?
The salts of Alkali metals are very soluble in water.
A number of alkaline earth metal compounds are not appreciably water soluble.
What is the trend between the solubility of Alkaline Earth Sulfates and Cation Size?
The solubility of Alkaline Earth Sulfates is found to decrease with increasing cation size.
BeSO4 is very _____, and BaSO4 is very _____.
Soluble-Insoluble
BaSO4 is found to _____ out of solution.
Precipitate
All of the Alkaline Earth Metals exist in their compounds and in solutions as _____ cations.
M 2+
What will happen if an Alkaline Earth Metal and an anion are mixed in solution (assuming that the resulting compound is insoluble)?
An Alkaline Earth salt will precipitate.
Beryllium is _____ and Radium is _____.
Poisonous-Highly Radioactive BP-RR
Which group do Halogens occupy?
7
_____ exist as diatomic molecules.
Halogens
What is a tendency of Halogens?
They tend to gain electrons and form X- anions.
Why are Halogens Oxidizing Agents?
Because they tend to oxidize (remove electrons from) other species.
How is a Halide written?
Y-
What is the reaction when a halogen is mixed with a halide?
X2+ 2Y (-) —-> 2X (-) + Y2
Under what conditions will the Halogen and Halide interaction result the way it does?
The reaction will only occur if X2 can remove electrons from Y- . In other words, X2 must be a better oxidizing agent than Y2).
What would happen if Y2 was a better oxidizing agent than X2?
The reaction would proceed in the opposite direction, meaning it wouldn’t happen.
In the reaction of halogens and halide ions, what is X said to be?
X is said to be reduced.
What is the reaction between a halogen molecule and a halide ion commonly called? Why?
Because the overall reaction consists of an oxidation reaction occurring simultaneously with a red deduction reaction, it is called a redox reaction.
How will we be able to determine solubility trend for the Alkaline Earth Group?
By performing simple solubility tests with several Alkaline Earth Metals.
How will we be able to determine the relative oxidizing strengths of several halogens/
By mixing solutions of halogens and halide ions. We can also use the characteristic colors of halogens to inform us of chemical reactions.
_____ have no color in water solution and are not soluble in organic solvents, such as hexane.
Halide Ions
What is the color of Bromine in Hexane?
Orange.
Define Oxidation
Loss of Electrons. OL
Define Reduction
Gain of electrons. RG
Define Oxidizing Agent
Causes oxidation by the removal of electrons from other species. In the process, the oxidizing agent is reduced.
True or False: The strongest oxidizing agent is best at causing other substances to be oxidized. Conversely, the strongest oxidizing agent is the most easily reduced species.
TRUE
Which elements will NOT be used in this experiment?
Beryllium-Radium-Astatine-Fluorine. BRAF
Which ions in this experiment are spectator ions?
NO3- ; H+ ; Na+ ; NH4+ ; K+. NH-NNK
If the solution forms a precipitate with your unknown, what can you infer?
If the solution forms a precipitate, you know for sure what the unknown cation is. If it doesn’t, you know one cation that the unknown is not.
What will the unknown contain?
One Halide Ion and One Alkaline Earth Cation
What is the trend for atomic radius?
Increasing from right to left and top to bottom.
How do you tell if something is better oxidizing agent than something else?
For example, let’s say we have X and Y (both are oxidizing agents). In solution, X is red and Y is green. Once they turn into their ion form in the reactions they undergo, they are colorless. When a solution of X is mixed with one containing Y-, the solution goes from red to green. Since there was a color change from red to green, X would be a better oxidizing agent.
