The periodic table

Cells with text in red are gaseous at room temperature.
Cells with text in green are liquid at room temperature.
Cells with text in black are solid at room temperature.
Cells with a dashed red outline are not found naturally on earth.
Elements 43, 61, and 84 and greater are only known as radioactive.

Subject classification: this is a chemistry resource .

How to use this periodic table

The periodic table lists all the known elements. There are 114 currently known and officially named. Elements 113, 115, 117, and 118 have been reported but not fully substantiated.

The periodic table arranges the elements according to their atomic number and fits them into a logical pattern. There are 18 columns that divide the elements into groups with closely related physical properties. Rows, or periods, help list elements in order of mass. Properties of elements change in systematic ways throughout the periodic table.

Groups and Periods

The periodic table is arranged into groups or columns, and periods or rows.

Groups

Elements in the same group, or family, have similar properties. Elements from the same group are found in vertical columns. Some groups are given non-scientific names, such as the halogens, noble gases, alkaline metals, and the alkaline-earth metals. Elements in the same group act similarly because they have the same valence electron configuration.

Periods

Each period represents the filling up of orbitals generated by the principal quantum number.

Non-metals

Non-metals are found on the top-right corner of the p-block elements. These elements tend to gain electrons when forming a bond with metals, or share electron between two non-metals to form a covalent bond. The boxes are also skyblue in colour.

Alkaline Metals

Alkaline metals are known as the most reactive metals. This can be observed by their reaction with water, for example. Their reactivity is attributed to the low ionization energy of the outermost electron in the atom. Their most common oxidative state is +1.they tend to lose 1 electron to complete their outer shells whatever.

Alkaline-Earth Metals

Alkali-Earth Metals have the second lowest ionization energy. Their most common oxidation state is +2.

Transition Metals

The atoms of the transition metals have more complicated electron arrangements than other atoms. The d orbitals of these elements are being filled. This group contains many well known metals, such as iron (Fe), nickel (Ni), copper (cu), mercury (Hg), and Gold (Au).

Poor Metals

The poor metals consist of aluminum, gallium, indium, thallium, tin, lead, and bismuth.

Metalloids

Metalloids roughly form a staircase line in the periodic table. This line divides metals and nonmetals. The elements around this partition have intermediate metal- and non-metal-like properties. Many of them can be used as semiconductors.

Halogens

All halogens are missing just one electron to fill their valence electron shell. For this reason, in most chemical reactions, halogens tend to gain one electron. halogens always exists as diatomic molecules. Going down the group, the color of elements increase; due to decreasing effective nuclear charge, atomic radius increase and electronegativity decreases. Halogens are not always in -1 oxidation state; when reacting with other more electronegative atoms, they give positive oxidation states. Examples are Cl₂O₇, and BrO^-.

Noble Gases

The noble gases have a full valence electron shell. For this reason, noble gases do not normally react with other elements, hence their former title inert gases. In fact, until 1962, they were thought completely nonreactive. This group consists of the elements helium, neon, argon, krypton, and xenon. They all are colorless gases (nonmetals). If you look at any periodic table, the density of the the noble gases increase as you go downwards. This is because the mass of the atoms gets larger.

Lanthanoids

Lanthanoids are the first elements to have electrons in an f orbital. Electrons are added to the f orbital to create the next element until element number 72, Hafnium.

Actinoids

The actinoids are radioactive elements. Their radioactivity is due to the fact that any nucleus with greater than 82 protons cannot be stable. They are related to the lanthanoids. The actinoids are the second groups of elements to add electrons to the f orbital.

Undiscovered

There are some undiscovered elements on the periodic table. However, due to the understanding of periodic table positions, their descriptions can be estimated.

Fun Facts

• Iridium and Osmium have the greatest density
• Francium is the least electronegative element and Fluorine is the most electronegative element

See Also

• The Periodic Table
• Periodicity
• List of Elements and their Symbols
• List of Elements and their Symbols 2