Periodic Properties Test - 7

A diagonal relationship is said to exist between certain pairs of diagonally adjacent elements in the second and third periods of the periodic table. These pairs (lithium (Li) and magnesium (Mg), beryllium (Be) and aluminium (Al), boron (B) and silicon (Si) etc.) exhibit similar properties; for example, boron and silicon are both semiconductors, forming halides that are hydrolysed in water and have acidic oxides.

The element whose configuration is 1s², 2s², 2p⁶, 3s² is a metal as it can lose 2 electrons to attain stable noble gas configuration.

The ionic radius of a metal is less than its atomic radius because metal forms positive ions due to low ionisation energy. Since positive ions are formed by loss of electrons from valence shells, but nuclear charge remains same, thus, the ionic radius of metal is smaller in size as compared to their source atom.

As we move down a group, atomic radii increase.
Option (1) is correct as the halogens are arranged in the increasing order of atomic radius.

Since the value of fourth ionisation energy is very high, so there are three valence electrons in the element.

The tendency to lose electrons increases as we go down a group because the atomic radius increases and the ionisation energy decreases. So, in the case of alkali metals, Fr has the highest tendency to lose electrons.

1s², 2s², 2p⁶, 3s¹ represents the configuration of sodium. After losing one electron, it acquires the stable electronic configuration of Neon. Hence, the second ionization energy will be exceptionally high.