Guide
1
First of all, you come to the aid of the periodic table.Looking at it, you'll see that each chemical element is not only their exact locations, but also an individual serial number.For example, it is one of hydrogen, carbon y - 6, for gold - 79 and so forth.
2
This sequence number describes the number of protons in the nucleus, ie, the positive charge of the nucleus of an atom.As the atom in the normal neutral state, the positive charge must be balanced by a negative charge.Consequently, the hydrogen - one electron, c
arbon - six electron , for gold - seventy-nine electrons .
3
But how to determine the number of electrons in atom , if the atom is, in turn, is part of a more complex molecule?For example, what is the number of electrons in atoms of sodium and chlorine, if they form a molecule well-known to all of you regular table salt?
4
And then there is nothing difficult.Start with the fact that write the formula of the substance, it will be as follows: NaCl.From the formula, you will see that a molecule of table salt consists of two elements, namely an alkali metal sodium and chlorine gas halo.But this is not neutral atoms of sodium and chlorine, and their ions.Chlorine to form an ionic bond with sodium, thus "pulled" to himself one of its electrons , and sodium, respectively, it "gave".
5
Again, look at the periodic table.You will see that sodium has a serial number 11, chlorine - 17. Therefore, now that the sodium ion is 10 electron , from chlorine ion - 18.
6
acting according to the same algorithm can be easily determined number of electrons in any chemical element, whether in the form of a neutral atom or ion.