• What are the groups of the periodic table?
• What are the groups in the periodic table?
• Periods of the periodic table

We explain what the groups of the periodic table are and the characteristics of each one. Also, the periods of the periodic table.

The elements of the same group have similar chemical properties.

What are the groups of the periodic table?

In chemistry, the groups of the Periodic Table are the columns of elements that compose it, corresponding to families of chemical elements They share many of their atomic characteristics.

In fact, the primary function of the Periodic table, created by the Russian chemist Dmitri Mendeleyév (1834-1907), is precisely to serve as a diagram of classification and organization of the different families of known chemical elements, so that the groups are one of its most important components.

These groups are represented in the columns of the table, while the rows constitute the periods. There are 18 different groups, numbered from 1 to 18, each of which groups a variable number of chemical elements. The elements of each group have the same number of electrons in their last atomic shell, which is why they have similar chemical properties, because the chemical properties of chemical elements are strongly related to the electrons located in the last atomic shell.

The numbering of the different groups within the table is currently established by the International Union of Pure and Applied Chemistry (IUPAC, for its acronym in English) and corresponds to the Arabic numbers (1, 2, 3 ... 18), in replacement of the traditional European method that used Roman numerals and letters (IA, IIA, IIIA ... VIIIA) and the American method that also used Roman numerals and letters, but in a different arrangement than the European method.

• IUPAC. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18.
• European system. IA, IIA, IIIA, IVA, VA, VIA, VIIA, VIIIA, VIIIA, VIIIA, IB, IIB, IIIB, IVB, VB, VIB, VIIB, VIIIB.
• American system. IA, IIA, IIIB, IVB, VB, VIB, VIIB, VIIIB, VIIIB, VIIIB, IB, IIB, IIIA, IVA, VA, VIA, VIIA, VIIIA.

In this way, each element present in the periodic table always corresponds to a specific group and period, which reflect the way to classify the periodic table. matter that mankind has scientifically developed.

What are the groups in the periodic table?

Next, we will describe each of the groups in the Periodic Table using IUPAC numbering and the old European system:

• Group 1 (before IA) or metals alkaline. Composed of the elements lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Ce) and francium (Fr), all common in plant ashes and of a basic character when they are part of oxides. They have low density, color their own and are usually soft. Hydrogen (H) is also usually included in this group, although it is also common for an autonomous position to be present among the chemical elements. Alkali metals are extremely reactive and must be stored in oil to prevent them from reacting with humidity of air. In addition, they are never found as free elements, that is, they are always part of some chemical compound.
• Group 2 (previously IIA) or alkaline earth metals. Composed of the elements beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba) and radium (Ra). The name "alkaline earth" comes from the name that its oxides used to receive (land).They are soft metals (although harder than those of group 1), of low density, good conductors and with electronegativity less than or equal to 1.57 according to the Pauling scale (scale established to organize the electronegativity values ​​of the atoms, where fluorine (F) is the most electronegative and francium (Fr) is the least electronegative). They are elements less reactive than those of group 1, but even so, they are still very reactive. The last on the list (Ra) is radioactive and has a very short half-life (the time it takes for a radioactive atom to disintegrate), so it is often not included in the lists.
• Group 3 (before IIIA) or scandium family. Composed of the elements scandium (Sc), yttrium (Y), lanthanum (La) and actinium (Ac), or by lutetium (Lu) and laurentium (Lr) (there is debate among specialists about which of these elements should be included in this group). They are solid and shiny elements, very reactive and with a great tendency to oxidation, good for conduct electricity.
• Group 4 (before VAT) or titanium family. Composed of the elements titanium (Ti), zirconium (Zr), hafnium (Hf) and rutherfordium (Rf), which are highly reactive metals and that, when exposed to air, acquire a red color and can ignite spontaneously (that is, they are pyrophoric). The last (Rf) of the family is a synthetic and radioactive element.
• Group 5 (formerly VA) or vanadium family. Composed of the elements vanadium (V), niobium (Nb), tantalum (Ta) and dubnium (Db), metals that have 5 electrons in their outermost atomic shells. Vanadium is quite reactive since it has a variable valence but the others are very little reactive, and the last one (Db) is a synthetic element that does not exist in the nature.
• Group 6 (formerly VIA) or chromium family. Composed of the elements chromium (Cr), molybdenum (Mo), tungsten (W) and seaborgium (Sg), all transition metals, and Cr, Mo and W are refractory. They do not present uniform electronic characteristics, despite their similar chemical behavior.
• Group 7 (formerly VIIA) or manganese family. Composed of the elements manganese (Mn), technetium (Tc), rhenium (Re) and bohrium (Bh), of which the first (Mn) is very common and the others extremely rare, especially technetium (which has no isotopes stable) and rhenium (which exists only in trace amounts in nature).
• Group 8 (before VIIIA) or iron family. Composed of the elements iron (Fe), ruthenium (Ru), osmium (Os) and hassium (Hs), transition metals that have eight electrons in their outer shells. The last one on the list (the Hs) is a synthetic element that exists only in the laboratory.
• Group 9 (before VIIIA) or cobalt family. Composed of the elements cobalt (Co), rhodium (Rh), iridium (Ir) and meitnerium (Mr), they are solid transition metals to temperature environment, of which the last (Mr) is synthetic and exists only in laboratories.
• Group 10 (before VIIIA) or family of nickel. Composed of the elements nickel (Ni), palladium (Pd), platinum (Pt) and darmstadtium (Ds), they are solid transition metals at room temperature, which are abundant in nature in their elemental form, except nickel, which has a enormous reactivity, which is why it exists by forming chemical compounds, and also abounds in meteorites. They have catalytic properties that make them very important in chemical industry and in aerospace engineering.
• Group 11 (before IB) or family of copper. Composed of the elements copper (Cu), silver (Ag), gold (Au) and roentgenium (Rg), called “minting metals” due to their use as an input for coins and jewelry. Gold and silver are precious metals, copper on the other hand is very useful industrially. The only exception is Roentgenium, which is synthetic and does not exist in nature. They are good electrical conductors, and silver has very high levels of heat conduction and reflectance of the light. They are very soft and ductile metals, widely used by mankind.
• Group 12 (previously IIB) or zinc family. Composed of the elements zinc (Zn), cadmium (Cd) and mercury (Hg), although different experiments with the synthetic element copernicium (Cn) could include it in the group. The first three (Zn, Cd, Hg) are abundantly present in nature, and the first two (Zn, Cd) are solid metals, and mercury is the only liquid metal at room temperature. Zinc is an important element for the metabolism of the living beings, while the others are highly toxic.
• Group 13 (formerly IIIB) or boron family. Composed of the elements boron (B), aluminum (Al), gallium (Ga), indium (In), thallium (Tl) and nihonium (Nh), they are also called “earthy”, since they are very abundant in the Earth crust, except for the last one on the list, synthetic and non-existent in nature. The industrial popularity of aluminum has led to the group also being known as the “aluminum group”. These elements have three electrons in their outer shell, they are metals of melting point very low, except boron which has a very high melting point and is a metalloid.
• Group 14 (before IVB) or carbonids. Composed of the elements carbon (C), silicon (Si), germanium (Ge), tin (Sn), lead (Pb) and flerovium (Fl), are mostly well-known and abundant elements, especially carbon, central to the chemistry of living beings. This item is non metallic, but as one descends in the group, the elements become more and more metallic, until they reach lead. They are also elements widely used in industry and very abundant in the earth's crust (silicon constitutes 28% of it) except for phlerovian, synthetic and radioactive with a very short half-life.
• Group 15 (before BV) or nitrogenoids. Composed of the elements nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), bismuth (Bi) and the synthetic element Moscovio (Mc), they are also known as polygenic, they are very abundant and very reactive being at high temperatures. They have five electrons in their outer shell, and as in the previous group, they acquire metallic properties as we progress through the group.
• Group 16 (before VIB) or chalcogens or amphigens. Composed of the elements oxygen (O), sulfur (S), selenium (Se), tellurium (Te), polonium (Po) and livermorio (Lv), they are with the exception of the last (Lv, synthetic) elements that are very common and used industrially. , the first two (O, S) also involved in the typical processes of the biochemistry. They have six electrons in their outer atomic shell and some of them tend to form compounds acidic or basic, hence their name of amphigens (from the Greek amphi-, "On both sides", and genos, "produce"). Among the group, oxygen stands out, of very small size and enormous reactivity.
• Group 17 (previously VIIB) or halogens. Composed of the elements fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astate (At) and tenese (Ts), they are usually found in their natural state as diatomic molecules that tend to form ions mononegative called halides. The last one on the list (the Ts), however, is synthetic and does not exist in nature. They are abundant elements in biochemistry, with enormous oxidation power (especially fluorine). Its name comes from the Greek words halos ("salt and genos ("Produce"), that is, "producers of salts."
• Group 18 (before VIIIB) or Noble gases. Composed of the elements helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), radon (Rn) and oganeson (Og), its name comes from the fact that in nature they usually Be in shape soda and they have a very low reactivity, which makes them excellent insulators for different industries. They have melting points and boiling very close, so that they can be liquid only in a small range of temperatures, and with the exception of radon (very radioactive) and oganeson (synthetic), they are in abundance in the terrestrial air and in the universe (especially helium, produced in the heart of stars by hydrogen fusion).

Periods of the periodic table

Just as there are groups, represented in the form of columns, there are also periods that are horizontal rows of the periodic table. The periods are directly related to the levels of Energy of each element, that is, with the number of electronic orbits that surround the nucleus.

For example, iron (Fe) is in the fourth period, that is, the fourth row of the table, since it has four electronic shells; While barium (Ba), having six layers, is in the sixth period, that is, the sixth row of the periodic table.