Question

9. State whether the following oxides are acidic, basic, neutral, or amphoteric: CO2, P2O5, SO3, MgO, K2O, Al2O3, CO.

10. Preferably without consulting reference material, write out the halogens as they appear in the periodic table, and indicate the trends in (a) physical state (s, l, or g) at room temperature and pressure, (b) electronegativity, (c) hardness of the halide ion, (d) colour.

Answer 1

9. When classifying the oxides, two processes are handy-

• To see their position in the periodic table, the Alkali and the Alkaline earth metal oxide are always basic oxides whereas the oxides of Non-metals are Acidic. It ultimately stands that, as we go from the Left to Right of the periodic table the acidic property of the oxides increases.
• Another method is to look for information about what the oxides give when they react with water. If the oxides react with water and give acids and the oxides react with bases to give salt, they are acidic oxides.

The classification is shown below-

Acidic oxides	Basic oxides	Amphoteric Oxides	Neutral Oxides

10.

a. The physical State of halogens (at room temperature and pressure)

• F - Gaseous
• Cl -Gaseous
• Br -Liquid
• I - Solid

As we go from top to bottom of the halogens, the metallic property increases.

b. Electronegativity - Electronegativity increases from Iodine to fluorine (bottom to top).Fluorine has the highest electronegativity among all the element (in the periodic table).

Halogens	Electronegativity
F	4.0
Cl	3.0
Br	2.8
I	2.5

c. Hardness or softness of the halide ion depends upon its size and the charge density (i.e. Charge by size ratio). As we go down the group, the size of the halide ion increases as well as its softness as the larger the size of the anion, it is subject to be more polarizable.

so among the halide ions,

is Hard ,also Hard (not much as fluoride), is Soft and the softer.

d. Color of halide ion-

The color of the halogens gets darker as we go from Fluorine to Iodine.

Halogens	Color
Fluorine	pale Yellow
Chlorine	Green
Bromine	Reddish-brown
Iodine	Violet