Periodic Table & Periodicity

Ionization potential of Na means energy required to convert of Na to Na+ ion.

Na $\to$ Na+ + e- IE = 5.1 ev Electron gain enthalpy of Na+ means energy required to convert Na+ ion to Na.

Na $\to$ Na+ + e-

= - 5.1 ev According to Lavoisier and Laplace law of thermochemistry, when we change the direction of reaction then the sign of energy also changes.

The melting point of gallium is very low (about 29.76°C or 85.57°F).

Therefore, gallium can melt just from the heat of one's hand.

The boiling point of gallium, on the other hand, is quite high (2400°C or 4352°F).

On the contrary, water boils at 100°C (212°F) under normal atmospheric pressure.

Therefore, inside boiling water, gallium would melt into a liquid but would not boil or evaporate, unlike the other elements listed.

Lithium (Li), Bromine (Br), and Cesium (Cs) have boiling points below 100°C, so they would turn into a gas in boiling water.

Element E is Selenium (Se) Electronic configuration of E is [Ar] 3d10 4s2 4p4 The element which is just above ‘E’ in periodic table is sulphur, its electronic configuration is [Ne] 3s2 3p4

Let's analyze the statements: A.

The electron gain enthalpy of $\mathrm{F}$ is more negative than that of $\mathrm{Cl}$.

This statement is incorrect.

The electron gain enthalpy of $\mathrm{F}$ is less negative than that of $\mathrm{Cl}$ due to its small size, which leads to increased electron-electron repulsion when an electron is added.

B.

Ionization enthalpy decreases in a group of the periodic table.

This statement is correct.

Ionization enthalpy generally decreases down a group of the periodic table due to the increase in atomic size, which results in a weaker attraction between the nucleus and the outermost electrons.

C.

The electronegativity of an atom depends upon the atoms bonded to it.

This statement is incorrect.

Electronegativity is a property of an atom that depends on the effective nuclear charge and the distance of the outermost electrons from the nucleus.

While the difference in electronegativity between atoms in a bond can affect the bond's polarity, the electronegativity itself does not depend on the atoms bonded to it.

D. $\mathrm{Al}_{2} \mathrm{O}_{3}$ and $\mathrm{NO}$ are examples of amphoteric oxides.

This statement is incorrect. $\mathrm{Al}_{2} \mathrm{O}_{3}$ is an example of an amphoteric oxide, meaning it can react with both acids and bases.

However, $\mathrm{NO}$ is not an amphoteric oxide; it is a neutral oxide.

Hence, the incorrect statements are A, C, and D.