..:: The Periodic Table ::..

The periodic table is an individual study of each of the elements which have similar properties. In 1869, chemist Dimitri Mendeleev was the first to propose a way to classify elements called the periodic table of elements, the elements in this table were ordered by their atomic weight.

When he prepared his own table, not known, Sc (pa = 45.1), gallium, Ga (pa = 69.7) and germanium, Ge (pa = 72.6) and others. Mendeleev Paraquad leave empty spaces in the future to discover more items arrived.

In 1913 Henry Moseley, an English scientist was based on X-ray experiments to determine the atomic numbers of elements. The periodic table by atomic number.

The periodic law is based on the physical and chemical properties of the parts where its periodic functions is according to the atomic number. According to this by placing the elements in increasing order of their atomic weights, is that there is a regularity, which a member of any group comes back every other element. (As the atomic weight of argon and potassium).

The periodic table is known as a source capable when verifying the information, when we want to know the characteristics of its components and which are metals, which are denser, heavier or reagents.

But the periodic table we know today was not always so, has changed as the years and looking at the similarities scientific discoveries which was a stunning disclosure by the discovery of each element.

PERIODS

1. is composed of the elements hydrogen and helium.

2. is the simplest member of the group typically inert elements called noble gases. Helium has two electrons in the layer k, which provides this layer.

Which consists of eight elements: lithium, beryllium, boron, carbon, nitrogen, oxygen, fluorine, and varies by neon.Cada have one more electron in the layer L.

3. has eight elements: sodium, magnesium, aluminum, silicon, phosphorus, sulfur, chlorine and argon. Sodium has one electron in the outer layer M.

4. consists of 18 elements: in addition to eight elements of groups I to VIII and also contains 10 transition elements.

5. composed of 18 elements, 10 transition elements (metals).

6. has 32 elements, the elements of groups I to VIII and 10 transition elements.

7. has an incomplete period is considered to be similar to the sixth period.

Where there is a general pattern for each period except the first. It begins with an alkali metal and the properties change from element to element.