The 14th International Conference on

Miniaturized Systems for Chemistry and Life Sciences

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Block (periodic table)





 

Block (periodic table)

There is an approximate correspondence between this nomenclature of blocks, based on electronic configuration, and groupings of elements based on chemical properties. The s-block and p-block together are usually considered main-group elements, the d-block corresponds to the transition metals, and the f-block encompasses nearly all of the lanthanides (like lanthanum) and the actinides (like actinium). Not everyone agrees on the exact membership of each set of elements. For example, some scientists regard the group 12 elements Zn, Cd and Hg as main group, rather than transition group, because they are chemically and physically more similar to the p-block elements than the other d-block elements. The group 3 elements are sometimes considered main group elements due to their similarities to the s-block elements. Groups (columns) in the f-block (between groups 3 and 4) are not numbered.

The p-block elements are unified by the fact that their valence electrons (outermost electrons) are in the p orbital. The p orbital consists of six lobed shapes coming from a central point at evenly spaced angles. The p orbital can hold a maximum of six electrons, hence there are six columns in the p-block. Elements in column 13, the first column of the p-block, have one p-orbital electron. Elements in column 14, the second column of the p-block, have two p-orbital electrons. The trend continues this way until column 18, which has six p-orbital electrons.

The d-block is on the middle of the periodic table and includes elements from columns 3 through 12. It appears since the 4th row. These elements are also known as the transition metals because they show a transitivity in their properties i.e. they show a trend in their properties in simple incomplete d orbitals. Transition basically means d orbital lies between s and p orbitals and shows a transition from properties of s to p.

The d-block elements are all metals which exhibit two or more ways of forming chemical bonds. Because there is a relatively small difference in the energy of the different d-orbital electrons, the number of electrons participating in chemical bonding can vary. This results in the same element exhibiting two or more oxidation states, which determines the type and number of its nearest neighbors in chemical compounds.

The d-block elements are unified by mostly having one or more chemically active d-orbital electrons. The d-orbitals can contain up to five pairs of electrons; they have a crucial importance for chemistry of elements in columns 3–11. Due to capacity of the d-subshell the block includes ten columns in the periodic table.

The f-block is in the center-left of a 32-column periodic table but is footnoted in 18-column tables. These elements are not generally considered part of any group. They are often called inner transition metals because they provide a transition between the s-block and d-block in the 6th and 7th row (period), in the same way that the d-block transition metals provide a transitional bridge between the s-block and p-block in the 4th and 5th rows.

The known f-block elements come in two series, the lanthanides of period 6 and the radioactive actinides of period 7. All are metals. Because the f-orbital electrons are less active in determining the chemistry of these elements, their chemical properties are mostly determined by outer s-orbital electrons. Consequently, there is much less chemical variability within the f-block than within the s-, p-, or d-blocks.

The f-block elements are unified by mostly having one or more of their outermost electrons in an f-orbital. The f-orbitals can contain up to seven pairs of electrons; hence, the block includes fourteen columns in the periodic table.







 

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