A compound has a formula of the form XF2, where X symbolizes a representative element

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x-symbolizes

#1

A compound has a formula of the form XF2, where X symbolizes a representative element.

a) If the compound were ionic, which group would you expect X to belong to? Explain

b)Name three properties that you would expect the ionic compound XF2 to have.

Answer:

a) Since the compound is XF2, we could assume that X belongs to group 2A (alkaline earth metals). This is due to F having a -1 charge. We can set up a simple algebra problem to help see this.
X+2F=0
X+2(-1)=0
X-2=0
X=2+
Elements in group 2A tend to form cations with a charge of 2+
Thus, leading us to believe it is from group 2A

b)

  1. good conductor of electricity in both solid and dissolved states

  2. The melting point and the conductivity increases on moving down the group due to the increase in the ionic character of the halides (They all will be ionic bonds and their ionic character increases as the size of the metal ion increase.)

  3. with the exception of Be2+, they all will have almost no solubility in water (Since on descending the group lattice energy decreases more rapidly than the hydration energy. Therefore whatever little solubility these fluorides have that increase down the group.)

4.Size will increase as you move down the group.