Periodic Table

Periodic Table

?

?

Two elements on the Periodic Table

History of the Periodic Table

Hydrogen is the first element

What is the periodic table?

The periodic is a table of the chemical elements arranged in order of atomic number, usually in rows, so that elements with similar atomic structure (and hence similar chemical properties) appear in vertical columns.

There are 118 elements.

In 1817 Dobereiner noticed that certain elements that were chemically similar could be grouped together in threes, for example, calcium, strontium, and barium; lithium, sodium, and potassium; chlorine, bromine, and iodine. In each group of three, the atomic weight of one element fell halfway between the atomic weights of the other two elements. The next milestone in the development of the periodic table was set by the Russian chemist Dmitri Mendeleev, who is generally acknowledged as the “father” of the modern periodic table.

How many elements are on the Periodic Table?

What is element #1?