Question

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Answer 1

yes-- gaps in the periodic table he noted there were undiscovered elements that would fill in these gaps.

more here:

http://en.wikipedia.org/wiki/Mendeleev's_predicted_elements

Answer 2

i think that is very good answer. i might say something about the traits of period 4 elemints.

http://en.wikipedia.org/wiki/Period_4_element

Answer 3

This all looks right to me. I was just looking to see if you should add anything else.

Answer 4

Great answer!

Answer 5

Looks like it to me.