Which of the following is correct?

• The number of electrons present in the valence shell of S in SF₆ is 12.

• The rates of ionic reactions are very slow

• According to VSEPR theory, SnCl₂ is a linear molecule.

• The correct order of ability to form ionic compounds among Na⁺, Mg²⁺ and Al³⁺ is  Al³⁺ >Mg²⁺ >Na⁺.

Observe the following statements :

I. The physical and chemical properties of elements are periodic functions of their electronic configuration.

II. Electronegativity of fluorine is less than the electronegativity of chlorine.

III. Electropositive nature decreases from top to bottom in a group.

The correct answer is :

• I, II and III are correct

• only I is correct

• only I and II is correct

• only II and III are correct

273.

The atomic numbers of elements A, B, C and D are Z - 1; Z; Z + 1 and Z + 2, respectively. If 'B' is a noble gas, choose the correct answers from the following statements-

1) 'A' has higher electron affinity.

(2) 'C' exists in +2 oxidation state. 

(3) 'D' is an alkaline earth metal.

• (1) and (2)

• (2) and (3)

• (1) and (3)

• (1), (2) and (3)

The correct order of reducing abilities of hydrides of V group elements is

• NH₃ < PH₃ < AsH₃ < SbH₃ < BiH₃

• NH₃ > PH₃ > AsH₃ > SbH₃ > BiH₃

• NH₃ < PH₃ > AsH₃ > SbH₃ > BiH₃

• SbH₃ > BiH₃ > AsH₃ > NH₃ > PH₃

A radioactive substance ₈₈X²²⁸ (IIA) emit 3α and 3β particles to form "Y". To which group of long form of the periodic table does "Y" belong ?

• IVA

• VA

• VIA

• VIIA

Which one of the following order is correct for the first ionisation energies of the elements?

• B < Be < N < O

• Be < B < N < O

• B < Be < O < N

• B < O < Be < N

Which one of the following is correct order of second ionisation potential of Na, Ne, Mg and Al?

• Al < Na < Mg < Ne

• Ne < Al < Na < Mg

• Mg < Al < Ne < Na

• Na < Mg < Ne < Al

The number of elements present in the fourth period is

• 32

• 8

• 18

• 2

Identify the most acidic oxide among the following oxides based on their reaction.

• SO₃

• P₄O₁₀

• Cl₂O₇

• N₂O₅

Match the following:

• A - 4; B - 3; C - 2; D - 1

• A - 3; B - 4; C - 1; D - 2

• A - 2; B - 1; C - 4; D - 3

• A - 4; B - 3; C - 1; D - 2