Consider an ion with the symbol Y 3— formed from a representative element. (5.2, 5.3) Required:
a. What is the group number of the element?
b. What is the electron-dot symbol of the element?
c. If Y is in Period 3, what is the element?
d. What is the formula of the compound formed from the barium ion and Y?

a) group 15

b) see diagram attached

c) phosphorus

d) Ba3Y2

Explanation:

Elements in group 15 have five valence electrons. To complete their octet, they can accept three electrons from other chemical species to form a trivalent anion such as Y^3-.

If Y^3- is in period 3, the element must be phosphorus. Also, considering that the valency of Y^3- is -3 and that of barium is +2, a compound formed between the both elements will have the symbol Ba3Y2.

consider the reaction below.

 no rx

at 500 k, the reaction is at equilibrium with the following concentrations.

[pci5]= 0.0095 m

[pci3] = 0.020

[ci2] = 0.020 m

what is the equilibrium constant for the given reaction?

0.042

0.42

2.4

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