Periodic law states that when the elements are arranged according to their atomic numbers, this allows elements with similar properties to appear at regular intervals. predict the group of elements and their number of valence electrons that will combine in a 3: 2 ratio to with calcium. a) boron, aluminum, gallium; 3 b) sulfur, selenium, polonium; 6 c) oxygen, tellurium, bismuth; 2 d) nitrogen, phosphorus, arsenic; 5

The correct answer is Option D.

Explanation:

Calcium is the 20th element of the periodic table having electronic configuration

This element will loose 2 electrons easily to form stable configuration. This is a metal and will form an ionic bond with a non-metal.

From the given options:

Option A: boron, aluminum, gallium; 3

These elements belong to Group 13 and are considered as metals having oxidation state of +3 because they easily loose 3 electrons. Thus, they will not form any compound with calcium.

Option B: sulfur, selenium, polonium; 6

These elements belong to Group 16 and are considered as non-metals having oxidation state of -2 because they easily gain 2 electrons. Thus, they form compound with calcium but in a 1 : 1 ratio.

Option C: oxygen, tellurium, bismuth; 6

These elements belong to Group 16 and are considered as non-metals having oxidation state of -2 because they easily gain 2 electrons. Thus, they form compound with calcium but in a 1 : 1 ratio.

Option D: nitrogen, phosphorus, arsenic; 5

These elements belong to Group 15 and are considered as non-metals having oxidation state of -3 because they easily gain 3 electrons. Thus, they form compound with calcium in a 3 : 2 ratio.

Hence, the correct answer is Option D.

answer: the value of enthalpy change will be -152.80 kj.

solution:

pressure = 1atm , temperature = = 298 k

given that pressure and temperature are same in both gases , the number of moles of both gases can be determined by the ideal gas equation.

according to reaction 3 moles no are reacting with 1 mol of ,then 0.49 mol of no will react with moles of ozone that is 0.16 moles of ozone. since, no is limiting reagent and is an excessive reagent.

enthalpy change for the reaction between the given volumes of the gases is :