The fundamental law governing the modern periodic table specifies that the characteristics of the elements are the periodic functions of their atomic number. These properties reappear at frequent intervals or at regular intervals, obey a specific pattern. The process is known as the periodicity of the elements.

The periodic properties of the elements are due to the recurrence of a particular electronic structure of the same number of electrons in the outermost orbit. The number of valence electrons in a given group remains the same. On the other hand, the number of valence electrons increases as we pass from left to right over some time.

Atomic size is the gap between the centre of the nucleus of the atom and its outer shell. In introductory chemistry, the atomic radius is the shortest distance between the atom’s nucleus and the atom’s outer shell.

The elements with greater non-metallic character are in the Periodic Table at the top right corner of the periodic table. It includes O2, F2 and so on. As we go from left to right in the Periodic Table, the metallic character declines, and the non-metallic character increases. And as we move from left to right, the number of valence electrons increases by one in each subsequent element, but the number of shells remains the same. The more powerful the nuclear charge, the more is the attraction between the nucleus and the electron. Consequently, the ability of the element to lose potential electrons decreases and results in a reduction of metallic character. In addition, the ability of the element to absorb electrons increases with an increase in the effective nuclear charge, thereby increasing the non-metallic nature of the element by switching from left to right over some time.

Ionisation is when the atom or molecule acquires a positive or negative charge by gaining or losing electrons through chemical changes. The resultant electrically charged atom or molecule is an ion. If the ion bears a negative charge, it is called anion, and if it carries a positive charge, it is called a cation.

The basic ionisation reaction is:

M → M+ + e–

Ionisation may result from electron loss from collisions with subatomic particles, collisions with other atoms, molecules and ions, or from interactions with electromagnetic radiation.

The electron affinity is the potential energy change of the atom when an electron is attached to a neutral gas atom to form a negative ion. The more negative the electron affinity, the more favourable the electron addition mechanism is. Not all elements form stable negative ions, in which case the electron affinity is zero or even positive.

When an atom in a molecule draws a common pair of electrons to itself, the tendency is known as electronegativity. It’s a dimensionless property, and it’s just a tendency. Essentially, it shows the net outcome of the tendency of atoms of various elements to attract bond-forming electron pairs.

The elements in the Periodic Table are in order of increasing atomic number. All these elements show several other trends, and periodic legislation and table formation can model their chemical, physical, and atomic properties. Understanding these patterns is achieved by studying the arrangement of the electron atoms; both elements prefer the formation of an octet and can gain or lose electrons to form the stable configuration.

In this chapter, we learned about the periodic table concept, along with some other related concepts.

1. Is electron affinity positive or negative?
2. The energy change is detrimental if the reaction is exothermic. It implies that the affinity of the electron is positive.
5. Who found electron affinity?
6. Electron affinity was a phenomenon discovered in 1901 in the light of the discovery of electron negativity by Linus Carl Pauling.
9. What is the trend in the atomic radii of the elements in the modern periodic table
10. The atomic/ionic radii of the elements increase when moving down the group in the modern periodic table due to new electron shells. The atomic radii of the elements usually decrease with time due to an increase in electronegativity and an increase in the effective nuclear charge on the outer shells.
13. What is a non-metal?
14. A chemical element that does not possess metal properties and can form anions, acid oxides, acids and stable hydrogen compounds is a non-metal—for example, boron, carbon & nitrogen.
17. Why is the atomic number so significant?
18. The atomic number is the number of protons in an atom. This number is very significant since it is unique to the atoms of a given substance. The atoms of the element all have the same number of protons, and each element has a different number of protons in its atoms.