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Periodic trends are specific patterns in the periodic table that show different things about a certain element, like how big it is and how it behaves in electricity. Electronegativity, ionisation energy, electron affinity, atomic radius, melting point, and metallic character are some of the main periodic trends. Periodic trends, which come from the way the periodic table is organised, are a great way for chemists to quickly predict an element’s properties. These trends are because the elements in their group families or periods have similar atomic structures, and because the elements are in a certain order.
Periodic Trends
There are certain patterns in the periodic table that highlight many aspects of an element, such as its size and electrical properties, through the use of periodic trends. Elements with high electronegativity and ionisation energies are more likely to have a metallic quality. Chemists can use periodic trends to swiftly forecast the properties of an element based on the layout of the periodic table. Because of the identical atomic structure of the elements in their respective groups or periods, and because of the periodic nature of the elements, certain tendencies exist.
Periodic Trends and Variation Of Properties
The elements in groups (vertical columns) of the periodic table have the same chemical properties. This is because each member of a group has the same number and location of electrons in their valence shells. On the periodic table, however, there are also some other patterns in the chemical properties. There are more metal-like atoms as we go down in a group, for example, Oxygen is at the top of group 16 (6A). Selenium is a semiconducting solid in the middle of the group; polonium is a silver-grey solid that conducts electricity at the bottom of the group.
A proton and an electron are added to the valence shell with each new element as we move across a period from left to right. It stays the same as we go down the elements in a group. The principal quantum number, on the other hand, goes up by one every time. An understanding of the electronic structure of the elements lets us look at some of the things that make them behave the way they do. These properties change from time to time because the electronic structure of the elements changes. Some of them are the size (radius) of each atom and ion, the energy it takes to make them ionise, and how they like each other.
Explore visualisations of the periodic trends that we talked about in this section (and many more trends). With just a few clicks, you can make three-dimensional versions of the periodic table that show the size of each atom or graphs of the ionisation energies of all the elements that have been measured.
Ionic Radius Trends
The periodic table contains a number of distinct patterns that highlight various qualities of a particular element, such as its size and its electrical capabilities. Elements with high electronegativity and ionisation energies are more likely to have a metallic quality. Chemists rely on periodic trends, which are derived from the periodic table’s organisation, to make fast predictions about an element’s attributes. To explain these tendencies, it is important to note that each element has a similar atomic structure within its group family or era.
Trends in Electronegativity
The ability of an atom to attract and bind electrons is referred to as its electronegativity, and it is a chemical property. To calculate electronegativity, there is no established procedure. A scale named after the American chemist Linus Pauling is most commonly used to measure electronegativity. Due to the qualitative nature of electronegativity, the Pauling scale assigns numbers that are not measurable in any way. Periodic tables list the electronegativity values for each element. The following is an example.
Electronegativity is the ability of an atom to attract and connect with electrons. atoms’ electronic configuration causes this property to exist. Atoms generally adhere to the octet rule (having the valence, or outer, shell comprising 8 electrons). Electron gain is much more energy-intensive than electron loss for elements on the left side of the periodic table because their valence shells are less than half-full. Therefore, while forming bonds, elements on the left-hand side of the periodic table typically lose electrons. To put it another way, elements on the right-hand side of the periodic table are more effective at gaining electrons in order to form a complete valence shell of eight. When an atom is more disposed to gain electrons, the more likely it is that the atom will attract electrons toward itself. This is the nature of electronegativity.
Trends in Ionisation Energy
To remove an electron from a neutral atom in gaseous form, an ionisation energy must be applied. Electronegativity is the polar opposite of ionisation energy conceptually. Cations are more easily formed when the atom’s energy level is lower. To put it another way: The more energy an atom has, the less likely it is that it will become an anion. Ionisation energies are often greater for elements on the right side of the periodic table because their valence shells are almost full. Because they are willing to give up their electrons and form cations, the elements on the left side of the periodic table have low ionisation energy. As a result, the periodic table shows an increase in ionisation energy from left to right.
Ionisation energy can also be influenced by electron shielding. It is the ability of an atom’s nucleus and valence electrons to be shielded by the inner electrons of the atom that is called electron shielding.
The first energy of ionisation is the energy of ionisation.
- X(g)→ X + (g)+ e− (1)
The second ionisation energy is as follows:
- X + (g)→ X2+ (g)+ e− (2)
The second, third, and so on follow the same periodic pattern as the first ionisation energy.
In general, the higher the atomic radius, the lower the ionisation energy. According to this observation, the ionisation energy is influenced by n (the primary quantum number) and Zeff (depending on the atomic number and indicating how many protons are present in an atom) (I
The ionisation energy increases as Zeff (the fundamental quantum number) increases over time but n (the principal quantum number) remains constant.
The ionisation energy drops as n grows and Zeff slightly increases down a group.
Trends in Electron Affinity
Electron affinity refers to an atom’s ability to take an electron. It is a quantitative measure of the energy shift that occurs when a neutral gas atom receives an electron, unlike electronegativity. The greater an atom’s affinity for electrons, the more negative its electron affinity value is.
Because each atom is larger than the atom above it, electron affinity tends to decrease as an element’s atomic number increases (this is the atomic radius trend, discussed below). As a result, the electron’s location in the larger atom is different from that of the electron in the smaller atom. An electron’s force of attraction is smaller when it is farther away from the positively charged nucleus. The electron affinity decreases as a result of this. Over the course of a period, as the attraction between atoms grows stronger, they shrink in size from left to right. In this way, the electron moves closer to the nucleus, resulting in an increase in electron affinity.
Trends in Atomic Radius
Half of the distance between two atoms’ nuclei is represented by the atomic radius (just like a radius is half the diameter of a circle). There is a problem with this theory, however, because not all atoms are generally bonded together in the same way. Covalent linkages bind some molecules, ionic crystals attract others, and metallic crystals hold them all together. However, the great majority of elements may form covalent molecules in which two atoms of the same kind are bonded together by a single covalent bond. Atomic radii are commonly used to describe the covalent radii of these compounds. Picometers are used to measure this distance. The periodic chart is littered with atomic radius patterns.
Conclusion
From the following article we can conclude that Periodic trends are those that explain specific properties of elements seen in the periodic table. Electronegativity, ionic radius, atomic radius, electron affinity, ionisation energy, chemical reactions of elements, and metallic character are periodic trends.
