Chemistry — the exact science therefore when mixing various substances it is just necessary to know their accurate proportions. For this purpose it is necessary to be able to find the mass of substance. It is possible to make it in various ways, depending on what sizes are known to you.
Inertia does not come down only to its mechanical manifestations. All real surely resists any influences, otherwise the world will not be able to exist. Visible manifestations of inertia can not be, but it does not vanish anywhere and never.
Atom of each chemical element is an own unique system, with certain, inherent only to it quantity of the smallest particles – neutrons, electrons and protons. In the center of atom there is a kernel positively charged at the expense of protons. In the same place also neutral particles – neutrons are located. Around the electrons bearing negative charges rotate.
To find quantity of protons in atom, define its place in Mendeleyev's table. Find its serial number in the periodic table. It will be equal to quantity of protons in an atomic nucleus. If isotope is investigated, look at couple of numbers, properties describing it, the lower number it will be equal to quantity of protons. In case the charge of an atomic nucleus is known, it is possible to learn quantity of protons, having divided its value into a charge of one proton.
Atom submits itself kind of the tiny copy of the Solar system. Only instead of the Sun in its center the massive kernel is located, and instead of planets elementary particles - electrons rotate. Atom electrically is neutral therefore the total negative charge of electrons has to be counterbalanced by a total positive charge of the same size. It occurs as the kernel consists of other elementary particles – protons and neutrons. Each proton bears the same charge in size as an electron, only with the opposite sign.