Why couldn't mendeleev organize the entire periodic table durning his rea search

The answer is :

Some elements were undiscovered at this time.

The explanation:

- Mendeleev depended on the atomic mass of the element in his organization of the entire periodic table , and this made him to put all  the elements which have the same chemical and physical properties with each other into vertical column called groups

- and this method created a mean of a gaps in the rows, he assumed that those gaps represent the undiscovered elements ,but the new periodic table is organized by the increasing in atomic numbers.  

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

24

answer: any goods being imported from another country may be subject to issued by the federal government are tariffs

explanation:  

tariffs are a tax on anything that are imported from abroad. government use them to protect and boost their local industries and the thought is that they encourage consumers to buy local instead of importing and they will hope will protect jobs and economy in the country that implements them