The Periodic Table Trends and Patterns

Mendeleev Suggested arranging the chemicals by physical properties and increasing atomic mass.

Periodic Table Elements are arranged according to physical properties and increasing atomic number. Zig-zag line separates metals and non-metals. Elements near the line have some metallic properties. These are called metalloids or semiconductors. They have properties of both metals and non metals They include B, Si, As, Te, At, Ge, Sb, Po.

Metals are shiny, malleable, ductile, and conduct (heat & electricity).

Non-metals do not conduct and break & crumble when struck.

Elements in the same vertical column are called families or groups. Each family has a number.

Horizontal rows are called periods.

Group I are the alkali metals – the most reactive metals Group I are the alkali metals – the most reactive metals. The presence of one electron in the outer orbit is associated with their reactivity. They form +1 ions and are never found in pure form.

Group II are the alkaline earth metals Group II are the alkaline earth metals. They all have 2 electrons in outer orbit and form +2 ion charges. They are highly reactive.

Group III through Group VI are named after the first element in each family. (ex. oxygen family)

Section in the middle is called Transition Metals Section in the middle is called Transition Metals. They are metallic elements. outer orbit has different numbers of electrons low reactivity, can occur as pure substances in nature can form multiple ion charges. Example Fe+2 and Fe+3 Transition metals

Groups VII are called the halogens – these are never found in pure form in nature. Often combine with alkali metals (eg. NaCl) They are the most reative non-metals. The outer orbit of all halogens need one electron to fill the orbits completely.

Group VIII are the noble gases – they are the lease reactive of all elements in the periodic table. They do not react under normal conditions because their outer orbits are full. Models look different but same atom

Hydrogen has separate properties from all other families but is often placed in Group I.

Bromine and Mercury are the only elements that are liquid at room temperature and pressure.

Periodic table Non-metals Hydrogen Metals Noble gases Alkaline earth metals Transition metals Halogens Alkali metals