I need someone to help with a list of questions for a Chemistry DBA i have.

Question

anonymous · Answer

1. Can you tell me how Dmitri Mendeleev arranged his periodic table? 
2. What are some similarities and differences between ionic and covalent bonds(valence e's, metals and nonmetals, transferring and sharing e's and which ones have the higher melting point)? 
3. What is the trend for ionization energy across a period and down a group? 
4. Name the following compounds 
Copper (II) Chloride 
dinitrogen trioxide 
Aluminum nitrate 
5. Explain the steps in finding the molar mass of Ca(NO3)2.

anonymous · Answer

1.on the basis of atomic mass
2-both non directional bonds,ionic is formed through transfer of electrons,covalent through sharing of electrons
ionic bonds stronger,higher melting points (usually)
4.$$CuCl2$$
N2O3

anonymous · Answer

atomic mass=sum of masses of individual elements
ca=40
N=14
0=16
add these up

xishem · Answer

3.) When looking at ionization energy only at a specific level (i.e., first ionization energy, second ionization energy), the ionization energy increases as you go from bottom to top of the periodic table and it increases as you go from left to right.

anonymous · Answer

kk didnt saw that one

xishem · Answer

Also, for 1...

He didn't arrange them purely on the basis of atomic mass. There were many other periodic tables already in existence at the time.

What made his table to special is that he did more with it -- he arranged it in such a way that elements with similar properties fell into the same columns or "periods".

anonymous · Answer

but he sorted them on the basis of mass..

xishem · Answer

But not only mass. If they were sorted purely on atomic mass, the periodic "table" would probably be either a straight line or arbitrarily assigned rows, and be much, MUCH less useful than it is.

But no, he intelligently arranged the table in such a way that it was also arranged by properties.

anonymous · Answer

I agree that the table was arranged based on element properties which is how we got groups such as the earth medals, noble gasses. He realized that the properties repeated themselves after he arranged them from the smallest to the largest. and this allowed him to guess that there wer some elements that have not been discovered yet.