It’s that time of the year again, when all the fun and joy disappear for a while. This is because you hear your parents and teachers asking you to be serious with your studies as the exams are about ...

Early periodic tables were incomplete, since many elements were unknown. Also, some elements were placed in groups with elements that were not similar to them. Mendeleev left gaps in his table for ...

the number of circles in the electronic configuration of an element is represented in the periodic table as the period number that element is situated in the number of electrons in the outermost shell ...