Group 4 elements

The Group 4 elements are a group of chemical elements in the periodic table. In the modern IUPAC nomenclature, Group 4 of the periodic table contains titanium (Ti), zirconium (Zr), hafnium (Hf) and rutherfordium (Rf). This group lies in the d-block of the periodic table. The group itself has not acquired a trivial name; it belongs to the broader grouping of the transition metals.

The three Group 4 elements that occur naturally are titanium (Ti), zirconium (Zr) and hafnium (Hf). The first three members of the group share similar properties; all three are hard refractory metals under standard conditions. However the fourth element rutherfordium (Rf), has been synthesized in the laboratory, none of them have been found occurring in nature. All isotopes of rutherfordium are radioactive. So far, no experiments in a supercollider were conducted to synthesize the next member of the group Unpentquadium (Upq). As Upq is a late member of period 8 element it is unlikely that this element will be synthesized in the near future.

Ti

Zr

Hf

 

Group 3 elements

The Group 3 elements are chemical elements comprising the third vertical column of the periodic table.
IUPAC has not recommended a specific format for the periodic table, so different conventions are permitted and are often used for group 3. The following d-block transition metals are always considered members of group 3:
•    scandium (Sc)
•    yttrium (Y)

Scandium (Sc)

Yttrium (Y)

When defining the remainder of group 3, four different conventions may be encountered:

• Some tables  include lanthanum (La) and actinium (Ac), (the beginnings of the lanthanide and actinide series of elements, respectively) as the remaining members of group 3. In their most commonly encountered tripositive ion forms, these elements do not possess any partially filled f orbitals, thus resulting in more d-block-like behavior.

• Some tables include lutetium (Lu) and lawrencium (Lr) as the remaining members of group 3. These elements terminate the lanthanide and actinide series, respectively. Since the f-shell is nominally full in the ground state electron configuration for both of these metals, they behave most like d-block metals out of all the lanthanides and actinides, and thus exhibit the most similarities in properties with Sc and Y. For Lr, this behavior is expected, but it has not been observed because sufficient quantities are not available. (See also Periodic table (wide) and Periodic table (extended).)

Some tables  refer to all lanthanides and actinides by a marker in group 3. A third and fourth alternative are suggested by this arrangement:

• The third alternative is to regard all 30 lanthanide and actinide elements as included in group 3. Lanthanides, as electropositive trivalent metals, all have a closely related chemistry, and all show many similarities to Sc and Y.

• The fourth alternative is to include none of the lanthanides and actinides in group 3. The lanthanides possess additional properties characteristic of their partially-filled f orbitals which are not common to Sc and Y. Furthermore, the actinides show a much wider variety of chemistry (for instance, in range of oxidation states) within their series than the lanthanides, and comparisons to Sc and Y are even less useful.

The term rare earth elements is often used for group 3 elements including the lanthanides but excluding the actinides.

Noble gases

A group 18 element is any chemical element from the last column of the standard periodic table.

For the first six periods, the group 18 elements are exactly the noble gases. However, the seventh member of group 18 (the synthetic element ununoctium) is probably not a noble gas.

Group 18 was previously called 'group 8A' or 'group 0'. According to the classical shell model for electrons, the group 18 elements have a fully filled outer shell, rendering them inert to most chemical reactions. This holds true for the first six elements of this group (though they tend to become slightly less inert with increasing periods). For the seventh period group 18 element (ununoctium), this "nobility" is predicted to break down due to relativistic effects.

Chalcogens

The chalcogens are the chemical elements in group 16 (old-style: VIB or VIA) of the periodic table. This group is also known as the oxygen family. It consists of the elements oxygen (O), sulfur (S), selenium (Se), tellurium (Te), the radioactive element polonium (Po), and the synthetic element ununhexium (Uuh).

Although all group 16 elements of the periodic table, including oxygen are defined as chalcogens, oxygen and oxides are usually distinguished from chalcogens and chalcogenides. The term chalcogenide is more commonly reserved for sulfides, selenides, and tellurides, rather than for oxides. Oxides are usually not indicated as chalcogenides. Binary compounds of the chalcogens are called chalcogenides (rather than chalcides; however, this breaks the pattern of halogen/halide and pnictogen/pnictide).

Although the word "chalcogen" is literally taken from Greek words being "copper-former," the meaning is more in line with "copper-ore former" or more generally, "ore-former." These electronegative elements are strongly associated with metal-bearing minerals, where they have formed water-insoluble compounds with the metals in the ores.

Nitrogen group

The nitrogen group is a periodic table group consisting of nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), bismuth (Bi) and ununpentium (Uup) (unconfirmed).

In modern IUPAC notation, it is called Group 15. In the old IUPAC and CAS systems, it was called Group VB and Group VA, respectively (pronounced "group five B" and "group five A", because "V" is a Roman numeral).^[1] In the field of semiconductor physics, it is still universally called Group V.^[2] It is also collectively named the pnictogens.^[3] The "five" ("V") in the historical names comes from the fact that these elements have five valence electrons

This group has the defining characteristic that all the component elements have 5 electrons in their outermost shell, that is 2 electrons in the s subshell and 3 unpaired electrons in the p subshell. They are therefore 3 electrons short of filling their outermost electron shell in their non-ionized state. The most important element of this group is nitrogen (chemical symbol N), which in its diatomic form is the principal component of air.

Binary compounds of the group can be referred to collectively as pnictides. The spelling derives from the Greek πνίγειν (pnigein), to choke or stifle, which is a property of nitrogen; they are also mnemonic for the two most common members, P and N. The name pentels (from the Latin penta, five) was also used for this group at one time, stemming from the earlier group naming convention (Group VB). These elements are also noted for their stability in compounds due to their tendency for forming double and triple covalent bonds. This is the property of these elements which leads to their potential toxicity, most evident in phosphorus, arsenic and antimony. When these substances react with various chemicals of the body, they create strong free radicals not easily processed by the liver, where they accumulate. Paradoxically it is this strong bonding which causes nitrogen and bismuth's reduced toxicity (when in molecules), as these form strong bonds with other atoms which are difficult to split, creating very unreactive molecules. For example N2, the diatomic form of nitrogen, is used for inert atmosphere in situations where argon or another noble gas would be prohibitively expensive.

The nitrogen group consists of two non-metals, two metalloids, one metal, and one synthetic (presumably metallic) element. All the elements in the group are a solid at room temperature except for nitrogen which is a gas at room temperature. Nitrogen and bismuth, despite both being part of the nitrogen group, are very different in their physical properties. For example, at STP nitrogen is a transparent nonmetallic gas, while bismuth is a brittle pinkish metallic solid.

Carbon group

The carbon group is a periodic table group consisting of carbon (C), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), and ununquadium (Uuq). In modern IUPAC notation, it is called Group 14. In the old IUPAC and CAS systems, it was called Group IVB and Group IVA, respectively.^[1] In the field of semiconductor physics, it is still universally called Group IV. The group was once also known as the tetrels (from Greek tetra, four), stemming from the Roman numeral IV in the group names, or (not coincidentally) from the fact that these elements have four valence electrons. Each of the elements in this group has 4 electrons in its outer energy level. The last orbital of all these elements is the p^2 orbital. In most cases, the elements share their electrons. The tendency to lose electrons increases as the size of the atom increases, as it does with increasing atomic number. Carbon alone forms negative ions, in the form of carbide (C^4−) ions. Silicon and germanium, both metalloids, each can form +4 ions. Tin and lead both are metals while ununquadium is a synthetic short-lived radioactive metal. Tin and lead are both capable of forming +2 ions.

Except for germanium and ununquadium, all of these elements are familiar in daily life either as the pure element or in the form of compounds. However, except for silicon, none of these elements are particularly plentiful in the Earth’s crust. Carbon forms a very large variety of compounds, in both the plant and animal kingdoms. Silicon and silicate minerals are fundamental components of the Earth’s crust; silica (silicon dioxide) is sand.

Tin and lead, although with very low abundances in the crust, are nevertheless common in everyday life. They occur in highly concentrated mineral deposits, can be obtained easily in the metallic state from those minerals, and are useful as metals and as alloys in many applications. Germanium, on the other hand, forms few characteristic minerals and is most commonly found only in small concentrations in association with the mineral zinc blende and in coals. Although germanium is indeed one of the rarer elements, it assumed importance upon recognition of its properties as a semiconductor.

Boron group

The boron group is the series of elements in group 13 (IUPAC style) in the periodic table. The boron group consists of boron (B), aluminium (Al), gallium (Ga), indium (In), thallium (Tl), and ununtrium (Uut). The group has previously also been referred to as the earth metals and the triels, from the Latin tri, three, stemming from the naming convention of this group as Group IIIB. These elements are characterized by having three electrons in their outer energy levels (valence layers). Boron is considered a metalloid, and the rest are considered metals of the poor metals groups. Boron occurs sparsely probably because of disruption of its nucleus by bombardment with subatomic particles produced from natural radioactivity. Aluminium occurs widely on earth and in fact, it is the third most abundant element in the Earth's crust (7.4%).

Alkaline earth metals

The alkaline earth metals are a series of elements comprising Group 2 (IUPAC style) (Group IIA) of the periodic table: beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba) and radium (Ra).^[1] This specific group in the periodic table owes its name to their oxides that simply give basic alkaline solutions. These oxides melt at such high temperature that they remain solids (“earths”) in fires. The alkaline earth metals provide a good example of group trends in properties in the periodic table, with well-characterized homologous behavior down the group. With the exception of Be and Mg, the metals have a distinguishable flame color, brick-red for Ca, magenta-red for Sr, green for Ba and crimson red for Ra.

Alkali metals

The alkali metals are a series of chemical elements forming Group 1 (IUPAC style) of the periodic table: lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr).^[1](Hydrogen, although nominally also a member of Group 1, very rarely exhibits behavior comparable to the alkali metals). The alkali metals provide one of the best examples of group trends in properties in the periodic table, with well characterized homologous behavior down the group.