Guide
1
famous periodic table, named in honor of the great Russian scientist, the discoverer of the law of the periodicity properties of chemical elements, chemistry plays a role of the original address and the information desk.Each chemical element assigned to it in a special box - "flat."By location of the cell in the table can accurately predict the "nature of the tenant," that is what the properties of the element.And like any true apartment, each cell element has its own serial number.
2
order to determine what is the total charge of the nucleus of an atom of an element, look at his number.The fact is that it is numerically equal to the number of protons in the nucleus of its atoms.And each proton, as already mentioned, the unit carries a positive charge.True protons in the nucleus in addition there are particles called neutrons.But they can easily be understood from its name, does not carry any charge.
3
For example, one of the most active elements of the periodic table - an alkali metal rubidium.It is in the first main group of the sixth period of the table.Its serial number of 37. Consequently, the net positive charge of the nucleus of an atom rubidium is 37.
4
Check it out.Any atom is neutral, therefore, rubidium atom must be 37 electrons to balance the charge of the proton nucleus.In one cell of the table, which takes rubidium, shows the composition of the electrons at each level.We consider how many electrons at all levels: 2 + 8 + 18 + 8 + 1 = 37. The total charge of electrons and protons = 0.
5
another example.Most of all existing refractory metal tungsten, located in the side of the eighth period of the sixth group at number 74. How many electrons in its atoms?Count: 2 + 8 + 18 + 32 + 12 + 2 = 74. Therefore, to tungsten atom was neutral, the total positive charge of the nucleus it must be equal to 74.The score became friends, all right.