Each atom belonging to every single group and period has a characteristic electronic configuration. This electronic configuration of the elements determines their several properties. It plays a major role in determining the chemical properties of the atoms such as valency, conductance, reactivity. If we look at it on a wider scale, electronic configuration determines every single chemical property of an element. Each element, in the ground state, has a unique electronic configuration and hence, each one of them differs from the other in many ways.
Electrons, although are so tiny, have a detrimental role in several reactions. The electronic configuration also determines which element would combine with which other element and in what ratio. Hence, the electronic configuration does play a huge role in the existence of every object in the surrounding.
Electronic Configuration in Periods of the Periodic Table
The elements in a periodic table are arranged in:
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The periods are basically the horizontal rows and the groups are the vertical columns of the modern periodic table. As we see in the image above, the modern periodic table has 7 periods and 18 groups. Across a period the atomic number of every consecutive element differs by 1. The electronic configuration between consecutive elements differs by only 1, across a period.
The value of the principal quantum number, that is n is incremented by 1 as we traverse across a period. As we traverse from left to right across a period, the Electronic Configuration of the elements increases, and hence the energy level of the atoms also increases.
The electronic configuration of hydrogen is 1s¹ whereas the electronic configuration of helium is 1s².
As we proceed down a group, the period number increases the number of subshells also increases.
The second period begins with lithium and boron which have 3 and 4 electrons respectively.
The 6th and 7th periods could be classified as the longest periods in the modern periodic table, as they also host lanthanides and actinides.
Electronic Configuration in Groups
As we have seen earlier, the modern periodic table consists of 18 groups. As we traverse down a group the electronic configuration in groups changes hugely. A new subshell is added to the elements as we traverse down a group. All the elements in a group have similar properties and also have the same valency. The elements belonging to a particular group have several similarities in their chemical properties and also form similar type of bonds, however, there are some exceptions.
Elements of each group have their characteristic feature. A list of the features is listed below.
Group 1: Group 1 consists of alkali metals. The valency of these metals is 1 and these metals are highly reactive. The metals of group 1 include Lithium, Sodium, Potassium, Rubidium, Cesium, and Francium.
Group 2: Group 2 elements are called alkali earth metals. These metals are named so because they are found in the earth's crust. The group 2 elements include Beryllium (Be), Magnesium (Mg), Calcium (Ca), Strontium (Sr), and Barium (Ba).
Transition metals include metals from group 3, group 4, group 5, group 6 until group 12. The transition metals constitute one of the largest sets of the periodic table. The elements classified as transition metals are strong and durable. A few of the prominent metals of the transition metal group include iron, manganese, copper, precious metals such as gold, silver, and platinum. These metals are also called d block elements.
Metalloids are a peculiar set of elements that have properties of both metals and nonmetals. The chemical and physical properties of metalloids are a perfect mixture of both metals and nonmetals. They are distinguished by a characteristic zig-zag line in the right-hand side of the periodic table ranging from group 13 to group 16. The following elements are classified as metalloids.
Boron (B), Silicon (Si), Germanium (Ge), Arsenic (As), Antimony (Sb), Tellurium (Te), Polonium (Po).
Nonmetals are the metals on the left-hand side of the periodic table. These elements are called so since they aren't metallic in nature. The prominent non-metals include the group 15 elements which have carbon. Carbon is one of the most important elements. This is because most naturally occuring materials consist of carbon. The non-metals also include nitrogen, oxygen, and other gases. Life isn't possible without any of these gases. Halogens and noble gases also come under nonmetals. Halogens are highly reactive gases whereas noble gases are the least reactive metals.