GENERAL REMARKS REGARDING ELEMENTS. 133 



their discovery, and, occasionally, some special points of interest, 

 should be noticed also. 



" All students having the facility for working in a chemical labora- 

 tory are strongly advised to make all those experiments and reactions 

 which will be mentioned in connection with the different substances 

 to be considered in this book. 



By adopting this mode of studying chemistry the student will soon 

 acquire a fair knowledge of chemical facts, yet he might know little 

 of the science of chemistry. In order to acquire this latter knowl- 

 edge he should study not only facts, but also the relationship existing 

 between them and between the laws governing the phenomena con- 

 nected with these facts. It is by this method only that the science 

 of chemistry can be successfully mastered. 



QUESTIONS. Why are not all the elements of equal importance? State the 

 physical and chemical properties of metals. How are metals distinguished 

 from non-metals ? What relation often exists between the atomic weights of 

 elements belonging to the same group? Explain the term allotropic modifica- 

 tion. Mention some elements capable of existing in allotropic modifications. 

 What relation exists between the properties of elements and the properties of 

 the compounds formed by their union ? In which cases are the syllables mono-, 

 di-, tri-, tetra-, and penta- used in chemical nomenclature? What use is made 

 of the syllables ous and ic, ite and ate, in distinguishing compounds from each 

 other? What are the principal features of the periodic law? 



