The Periodic Table

By the 1870’s many elements had been identified, therefore a method to organize the elements according to their properties was needed. Properties – the characteristics used to describe and identify a substance. Ex: shiny, dull, conductor of heat, chemically active, etc.

The Father of the Periodic A Russian chemist, Dmitri Mendeleev organized a method of grouping the elements by placing them in a table, The Periodic Table.

The Periodic Table Column = Group or Family 18 columns on the Periodic Table The Periodic Table arrangement makes it easy to remember the properties of elements. Elements with similar characteristics are grouped together as families, or groups. By looking at an elements position in the table, one can understand quite a bit of information, such as size, chemical properties, and physical properties.

Metals- elements that conduct electricity. Nonmetals- do not conduct electricity, have dull surfaces, and cannot be shaped by hammering or drawing into wires. Metalloids- have properties of both metals and nonmetals and are good semiconductors.

Metals, Nonmetals, and Semi-metals Nonmetals are on the right of the stair-step Metals are to the left of the stair- step Semi-metals, “metalloids,” touch the stair-step

6 C Carbon 12.01 ← atomic number ← element symbol ← element name ← atomic mass number The number located at the top of each box is the atomic number. This number is the number of protons and electrons in an atom. The number located at the bottom of each box is the atomic mass number. This number is the number of protons and neutrons in the nucleus of the atom. The letters in the center of each box is the element symbol. A chemical symbol is always in capital letters, except for 2 letter symbols. 2 letter symbols, the first letter is capitalized and the second letter is not. For example: Na, He, Mg.

7 rows on the Periodic Table The horizontal rows in the periodic table are called periods. All elements on a given period have the same number of energy shells in which electrons orbit the nucleus. These energy spaces are called electron shells. Row = Period 7 rows on the Periodic Table

The vertical columns in the periodic table are called groups or families. Each group is named according to properties of the elements. Column = Group or Family 18 columns on the Periodic Table

The Groups of the Periodic Table Column 1A – Alkali Metals – most reactive metals on the PT

Column 2A- Alkaline Earth Metals- still very reactive metals

Column 3A- Boron Family

Column 4A- Carbon Family

Column 5A- Nitrogen Family

Column 6A Oxygen Family

Column 7A- Halogens

Column 8A- Noble Gases

The “B Group” is the group of elements in the middle of the periodic table known as the transition metals.

The 2 rows at the very bottom of the periodic table make up the rare earth elements. The top row is the Lanthanide Series and the bottom row is the Actinide Series. Lanthanides Actinides