During the course of a period, as one moves from left to right, metallic properties diminish while nonmetallic features rise. It can be compared to the metallic and non-metallic properties of elements in terms of their properties. The halogens, on the other hand, are the elements on the extreme right of the periodic table that quickly obtain electrons and combine to create an anion. The alkalis, which are at the extreme left of the periodic table, readily lose electrons and create cations. The trends in properties shown above can be summarised as follows: the elements at both ends of the periodic table are highly reactive (note that noble gases have completely filled shells, so they are the least reactive), and elements in the middle of periodic table are the least reactive (note: noble gases have completely filled shells, so they are the least reactive). When energy is supplied to an atom while an electron is added, this is considered positive. When energy is released while absorbing an electron, this is referred to as a negative event. Increasingly negative electron gain enthalpy is observed as we move from left to right in a periodic table.

Second, the shielding effect increases along the group as the number of shells increases, which leads to a decrease in the ionisation energy as the number of shells increases in the group. This is owing to the fact that the number of shells grows as one moves down the group, resulting in the outermost electrons being further away from the nucleus and, as a result, the effective nuclear charge being less. When we look at the trend of ionisation enthalpy in the groups, we can observe that it drops from the top to the bottom of each group. As a result, ionisation energy normally increases from one period of the periodic table to the next across the table. Consequently, when the size of an atom shrinks, the attractive attraction between the nucleus and the electrons on the outermost shell of the atom grows. The atomic radius decreases as one moves from left to right in a period of time. The Enthalpy of Ionisation Is Measured As Moving from the top to the bottom of a group causes them to increase in size because the number of shells increases in proportion to the increase in atomic number. Atomic Radii and Ionic Radii Are Both Defined As Followsĭuring the course of a period, the atomic and ionic radii of elements decrease as they progress from left to right. Observe the trends in an element’s essential characteristics first. Following a thorough examination of the concepts, we can establish a link between chemical properties and the fundamental properties of elements. The ability to recognise periodicities in the fundamental properties of elements (atomic and ionic radius, ionisation enthalpy, and electron gain enthalpy) will allow you to conclude that an element’s electronic configuration is primarily responsible for the periodicity in its fundamental properties. For example, the atomic and ionic radii of elements decrease from left to right as they move through a period. The systematic arrangement of elements in a periodic table reveals periodic tendencies in the properties of elements that are revealed by the periodic table.

Trends of Chemical Reactivity in Periodic Table Atomic and ion radius, ionisation energy, and electron affinity all fall into this category. The electrical structure of the elements influences these properties. We can study some of the features that regulate the chemical behaviour of elements by understanding their electrical structure. The number of electrons in the valence shell does not change as we progress through the elements in a group, but the principal quantum number does. Polonium is a silvery-grey solid that conducts electricity at the bottom of group 16 (6A), while oxygen is a colourless gas at the top of the group.Ī proton and an electron are added to the valence shell for each element that crosses a period from left to right. For example, the metallic nature of the atoms rises as we proceed down a group. But there are other patterns in the periodic table as well. Members of a group have the same number and distribution of electrons in their valence shells, resulting in this resemblance. Identical chemical properties are shared by the elements arranged in periodic table groupings (vertical columns).

Reactivity in periodic table