Electronic configurations and types of elements:s,p,d,f blocks

Since long form of the periodic table is closely related to the filling of various orbitals present in the atoms of elements, the elements showing similar trends of filling of orbitals can be grouped together into blocks and the entire periodi table can be divided into four blocks. The division of the Periodic Table into s,p,d,f blocks is shown schematically in the fig. below

A block of the periodic table of elements is a set of adjacent groups. The term appears to have been first used by Charles Janet.The respective highest-energy electrons in each element in a block belong to the same atomic orbital type. Each block is named after its characteristic orbital; thus, the blocks are:

• s-block
• p-block
• d-block
• f-block

The s-Block elements

s-block elements are the elements found in Group 1 and Group 2 on the periodic table. Group 1 are the alkali metals which have one valence electron. They have low ionization energies which makes them very reactive. Group 2 is the alkali earth metals which have two valence electrons, filling their s sublevel.

The electron in their most outward electron shell are in the s-orbital. Elements in these are in the first two periodic table groups. The elements in group one are called the alkali metals. The elements in group two are called the alkaline earth metals.

Why is potassium considered as an S block element?

Group 1 of the Periodic Table consists of the elements: lithium, sodium, potassium, rubidium, caesium and francium. They are collectively known as the alkali metals. These are so called because they form hydroxides on reaction with water which are strongly alkaline in nature.

The p-Block elements

The p-block is the area of the periodic table containing columns 3A to column 8A (columns 13-18), not including helium. There are 35 p-block elements, all of which have valence electrons in the p orbital. The p-block elements are a very diverse group of elements with a wide range of properties.

The p-block elements are found on the right side of the periodic table. They include the boron, carbon, nitrogen, oxygen and flourine families in addition to the noble gases. The noble gases have full p-orbital's and are nonreactive. p block orbital.

The group that resides in column 8A is called the noble gases. Their p orbitals contain six electrons. This group is nonreactive and generally does not bond with other elements, preferring to exist by themselves. These gases are clear and odorless.

The general electronic configuration of P block elements

In p-block elements the last electron enters the outermost p orbital. ... Consequently there are six groups of p–block elements in the periodic table numbering from 13 to 18. Boron, carbon, nitrogen, oxygen, fluorine and helium head the groups. Their valence shell electronic configuration is ns2 np1-6(except for He).

Metalloids have properties of both metals and nonmetals, but the term 'metalloid' lacks a strict definition. All of the elements that are commonly recognized as metalloids are in the p-block: boron, silicon, germanium, arsenic, antinomy, and tellurium.

The d-Block elements (Transition Elements)

The d-block elements are called transition metalsand have valence electrons in d orbital's.

The transition elements are also known as the d-block elements, because while the outermost level contains at most two electrons, their next to outermost main levels have incompletely filled d sub-orbitals, which are filled-up progressively on going across the periodic table from 8to 18 electrons.

The general electronic configuration of D block elements These series of the transition elements are shown in Table 8.1. In general the electronic configuration of these elements is (n-1)d1–10 ns1–2. The (n–1) stands for the inner d orbitals which may have one to ten electrons and the outermost ns orbital may have one or two electrons.

Properties of transition elements include:

• have large charge/radius ratio
• are hard and have high densities
• have high melting and boiling points
• form compounds which are often paramagnetic
• show variable oxidation states
• form coloured ions and compounds
• form compounds with profound catalytic activity

The f-Block elements (Inner Transition Elements)

The f-block elements,found in the two rows at the bottom of the periodic table, are called inner transition metalsand have valence electrons in the f-orbital's.

The f-block is in the center-left of a 32-column periodic table but in the footnoted appendage of 18-column tables. These elements are not generally considered as part of any group. They are often called inner transition elements 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 metal 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.

F-block elements are unified by having one or more of their outermost electrons in the f-orbital but none in the d-orbital or p-orbital. The f-orbitals can contain up to seven pairs of electrons; hence, the block includes fourteen columns in the periodic table.

Metal, Non-metals and Metalloids

Metals

P-block metals have classic metal characteristics: they are shiny, they are good conducters of heat and electricity, and they lose electrons easily. Generally, these metals have high melting points and readily react with nonmetals to form ionic compounds . Ionic compounds form when a positive metal ion bonds with a negative nonmetal ion.

Of the p-block metals, several have fascinating properties. Gallium, in the 3rd row of column 13, is a metal that can melt in the palm of a hand. Tin, in the fourth row of column 14, is an abundant, flexible, and extremely useful metal. It is an important component of many metal alloys like bronze and solder.

Sitting right beneath tin is lead, a toxic metal. Ancient people used lead for a variety of things, from food sweeteners to pottery glazes to eating utensils. It has been suspected that lead poisoning is related to the fall of Roman civilization, but further research has shown this to be unlikely. For a long time, lead was used in the manufacturing of paints. It was only within the last century that lead paint use has been restricted due to its toxic nature.

Non Metals

In chemistry, a nonmetal (or non-metal) is a chemical element that mostly lacks metallic attributes. Physically, nonmetals tend to be highly volatile, have low elasticity, and are good insulators of heat and electricity; chemically, they tend to have high ionization energy electronegativity values, and gain or share electrons when they react with other elements or compounds. Seventeen elements are generally classified as nonmetals; most are gases (hydrogen, helium, nitrogen, oxygen, fluorine, neon, chlorine, argon, krypton, xenon and radon); one is a liquid (bromine), and a few are solids (carbon, phosphorus, sulphur, selenium, and iodine).

Moving rightward across the standard form of the periodic table, nonmetals adopt structures that have progressively fewer nearest neighbours. Polyatomic nonmetals have structures with either three nearest neighbours, as is the case (for example) with carbon (in its standard state of graphite), or two nearest neighbours (for example) in the case of sulfur. Diatomic nonmetals, such as hydrogen, have one nearest neighbour, and the monatomic noble gases, such as helium, have none. This gradual fall in the number of nearest neighbours is associated with a reduction in metallic character and an increase in nonmetallic character. The distinction between the three categories of nonmetals, in terms of receding metallicity is not absolute. Boundary overlaps occur as outlying elements in each category show (or begin to show) less-distinct, hybrid-like or atypical properties.

Metalloids

Metalloids have properties of both metals and nonmetals, but the term 'metalloid' lacks a strict definition. All of the elements that are commonly recognized as metalloids are in the p-block: boron, silicon, germanium, arsenic, antimony, and tellurium. Metalloids tend to have lower electrical conductivity than metals, yet often higher than nonmetals. They tend to form chemical bonds similarly to nonmetals, but may dissolve in metallic alloys without covalent or ionic bonding. Metalloid additives can improve properties of metallic alloys, sometimes paradoxically to their own apparent properties. Some may give a better electrical conductivity, higher corrosion resistance, ductility, or fluidity in molten state, etc. to the alloy.

Boron has many carbon-like properties, but is very rare. It has many uses, for example a P type semiconductor dopant.

Silicon is perhaps the most famous metalloid. It is the second most abundant element in Earth's crust and one of the main ingredients in glass. It is used to make semiconductor circuits, from large power switches and high current diodes to microchips for computers and other electronic devices. It is also used in certain metallic alloys, e.g. to improve casting properties of alumimium. So valuable is silicon to the technology industry that Silicon valley in California is named after it.

Germanium has properties very similar to silicon, yet this element is much more rare. It was once used for its semiconductor properties pretty much as silicon is now, and it has some superior properties at that, but is now a rare material in the industry.

Arsenic is a toxic metalloid that has been used throughout history as an additive to metal alloys, paints, and even makeup.

Antimony is used as a constituent in casting alloys such as printing metal.

1. Not always considered as metalloids
2. Carbon, in the same column with silicon and germanium, electrically fairly conductive unlike most other nonmetals, and to an extent preferred as a trace constituent in certain metallic alloys such as steel
3. Phosphorus has metallurgical uses among others, e.g. a constituent of some copper alloys
4. Selenium, once used as a semiconductor material, and also used to improve properties of metallic alloys
5. Aluminium is generally considered a metal, but it has some metalloid/non-metal properties such as negative oxidation states.