Give reasons why: (a) Hydrochloric acid cannot form an acid salt. (b) Electronegativity increases across a period.

Given below are a few elements. Li, Li, K, Ca, F Identify the element which: (a) has the least atomic radius. (b) has two valence electrons. (c) is the most electropositive.

Elements P, Q, and R are in the same period of the modern periodic table. P readily loses its one valence electron to form a stable ion. Q shares its electrons in bonding but does not form ions easily. R has high electronegativity. Answer the following questions based on the above information: (a) Which element would be most difficult to reduce among P, Q and R? (b) Which element is expected to have the smallest atomic radius among P, Q and R? (c) Arrange P, Q and R in order of decreasing ionisation potential.

Element A belongs to group 15 and period 2 of the Periodic Table. (a) Identify the element A. (b) Write the formula of the compound formed when element A combines with hydrogen. (c) Draw the dot (•) and cross (×) structure of the compound formed in (b) above.

Give a reason for each: (a) Ionisation potential decreases down a group. (b) Ionic compounds do not conduct electricity in the solid state.

Give reasons for the following: (a) Inert gases do not form ions. (b) Covalent compounds have a low melting and boiling point.

Given below are two sets of elements from two different periods. Name the element with the highest ionisation potential in each of the following sets. (a) Al, Cl, Mg (b) Ne, O, F

The atomic number of two atoms ‘X’ and ‘Y’ are 14 and 8 respectively. State: (a) the period to which ‘X’ belongs. (b) the formula of the compound formed between ‘X’ and ‘Y’. (Do not identify X and Y)

Arrange the following as per the instruction given in the brackets: (a) Al, K, Mg, Ca (decreasing order of its reactivity) (b) N, Be, O, C (increasing order of non-metallic character) (c) P, Si, F, Be (decreasing order of valence electrons)

Fill in the blanks with the choices given in the brackets: (a) Metals are good ............... [oxidizing agents /reducing agents] (b) Non-polar covalent compounds are ............... [good / bad] conductors of heat and electricity. (c) Higher the pH value of a solution, the more is ............... [acidic / alkaline] it is. (d) ............... [Silver chloride / Lead chloride] is a white precipitate that is soluble in excess of Ammonium hydroxide solution. (e) Conversion of ethene to ethane is an example of ............... . [hydration / hydrogenation]

State the terms/process for the following: (a) The energy released when an atom in the gaseous state accepts an electron to form an anion. (b) Tendency of an element to form chains of identical atoms. (c) The name of the process by which Ammonia is manufactured on a large scale. (d) A type of salt formed by partial replacement of hydroxyl radicals with an acid radical. (e) The ratio of the mass of a certain volume of gas to the same volume of hydrogen measured under the same conditions of temperature and pressure.

X, Y & Z are three metallic atoms in successive order belonging to the same group such that atomic radii of ‘X’ is the smallest. Which of the three atoms is the best reducing agent? (a) X (b) Y (c) Z (d) All three have the same reducing power