In periodic table, elements are categorized based on their electronic structure. This makes the recurring element properties noticeable in this table. Here is a look at the periodic table trends of electronegativity, atomic radius, electron affinity, metallic character and ionization energy.
Periodic Table Trends
Electronegativity is the ability of an atom to pull electrons towards it. It shows how an atom can swiftly form a chemical bond. Electronegativity usually rises from left to right. It sees a decreasing trend when you move down a group. However, there are exceptions to it at times. Two atoms have a greater chance of forming a chemical bond when the difference between their electronegativity values is larger. The electronegativity of atoms is affected by the distance between the nucleus and the valence electrons and the atomic number.
- Atomic Radius
This is basically the distance covered from the outermost stable electron to the nucleus. Ionic radius, on the other hand, is the distance amid two atomic nuclei touching one another.
As one goes downwards in the periodic table, elements with more protons are seen. These elements gain an electron energy shell and hence the atoms become larger. As one goes across a row of the periodic table, greater number of electrons and protons can be observed. Here, the former are closer to the nucleus and thus the size of the atom declines.
- Electron Affinity
Electron Affinity means how swiftly an atom accepts electron. It declines moving down a column and rises while moving from left to right in a periodic table. The value of an electron affinity in an atom is basically the energy acquired on the addition of an electron. It is also the energy released on the removal of a single-charged anion. This is mainly dependent on the arrangement of the outer electron shell. The elements present within a group contain similar affinity. Noble gas elements have almost zero electron affinity.
- Metallic Character
Most of the elements in this table are metals. This implies that they have a metallic character. Ductility, thermal conductivity, metallic luster, malleability and high electrical and thermal conductivity are some of the properties of metals. An element is said to be metallic in character if the value of its ionization energy, electron affinity and electronegativity is lower. Metallic characters decline as they go across a periodic table.
NOTE: The above mentioned trends are general, do not include exceptions.
- Ionization Energy
It is the lowest amount of energy required to draw an electron away from an atom when in the gaseous state. Ionization energy sees a rise when you move from left to right across a period. This is because the number of protons increases in this direction and these are able to pull the electrons strongly.
When you go down a group, there is a decline in the ionization energy. This is because of the addition of an electron shell that moves the outermost electron further away from the nucleus of the atom.