You can't make it come, it will do that on its own, but eating healthy and not having your weight fluctuate dramatically helps keep it regular. Also, if you are new to your period, it could be irregular for the first 3 years, don't worry, if it doesn't come on time your not necessarily pregnant
no - gases are few in number - metals make up most of the periodic table
You dont
118 elements.
No, Dmitri Mendeleev in Russia developed the first periodic table.
No they did not.
To make study of elements easier.To classify elements.
knives, swords,etc
Californium was discovered in 1950.
asasd
Henry Mosely!
Aluminium
1869