Periodic Table – Blocks
Elements can be classified by the last energy level that their electrons fill. There are 4 types of electron orbitals (s, p, d & f) and where these orbitals are on the periodic table.
The elements in groups 1 & 2 and Helium are the s block elements.
The two rows at the bottom of the periodic table, detached from the table are the f block elements.
The elements in groups 13-18 (except Helium) are the p block elements.
The elements in groups 3-12 are the d block elements.
Periodic Table - State at 298 K
Elements can be classified by their state at room temperature (298 K). Most elements are solid at room temperature but there are 2 elements that are liquid and 11 elements that are gases at 298 K.
Hydrogen (H), Helium (He), Nitrogen (N), Oxygen (O), Fluorine (F), Neon (Ne), Chlorine (Cl), Argon (Ar), Krypton (Kr), Xenon (Xe) and Radon (Rn) are all gases at room temperature.
Mercury (Hg) & Bromine (Br) are liquid at room temperature.
All remaining elements are solid at room temperature.
Periodic Table - Metallic Character
Elements can be classified by their metallic character as being a metal, metalloid (semi-metal) or nonmetal.
Metals include all elements that are not considered a metalloid or nonmetal. Metals have the following properties:
Shiny metallic appearance.
Solid at room temperature (except Mercury).
High melting point.
High densities.
Malleable & ductile.
Good conductors of heat & electricity.
Metalloids (also known as semi-metals) include Boron (B), Silicon (Si), Germanium (Ge), Arsenic (As), Antimony (Sb), Tellurium (Te) and Astatine (At). Metalloids have the following properties:
Have properties of both metals and nonmetals.
Often used as semiconductors.
Nonmetals include all elements to the right of the metalloids and Hydrogen (H). Nonmetals have the following properties:
Solid nonmetals have little to no metallic luster.
Solid nonmetals are brittle.
High ionization energy.
Poor conductors of heat & electricity.
Periodic Table - Groups
The elements of the periodic table can also be classified by groups of similar properties.
Alkali Metals include all elements in group 1 except Hydrogen (H). Alkali metals have the following properties:
Lower densities than other metals.
React with water & air.
Stored in oil.
One valence electron.
Easily lose their valence electron to form a univalent cation (1+ charge)
Alkaline Earth elements include all elements in group 2. Alkaline earth elements have the following properties:
Harder, denser & stronger than alkali metals.
Two valence electrons.
Easily lose valence electrons to form divalent cations (2+ charge).
Transition Elements refer to groups 3 through 12. Transition elements have the following properties:
Referred to as B group elements.
Very Hard.
High melting & boiling points.
High electrical conductivity.
Lanthanides include elements 58-71. Lanthanides are:
Known as Rare Earth elements because they are rare on earth.
Actinides include elements 90-103. Actinides are:
Known as Rare Earth elements because they are rare on earth.
Chalcogens include all elements in group 16.
Halogens include all elements in group 17. Halogens have the following properties:
Have 7 valence electrons and only need 1 electron to fill their outer energy level.
High electronegativities.
Most reactive nonmetals, especially with alkali metals and alkaline earth metals.
Noble Gases include all elements in group 18. Noble gases have the following properties:
Known as inert gases.
All gases at room temperature.
Have full outer energy level.
High ionization energies but very low electronegativities.
Synthetic elements
There are 90 naturally occurring elements . The other elements on the periodic table are man-made and referred to as synthetic elements. The synthetic elements are : Technetium (Tc), Promethium (Pm ) and all elements with atomic numbers greater than Uranium (U).
Click on the "Group by" choice on the periodic table below to see the different ways to organize the elements.
