Long Answer TypeA, B, C are three elements, B is an inert gas element other than helium; with this information, complete the table given below:
| Element | Atomic No. | No. of electrons in the valence shell | Group to which element belongs |
| A | Z - 1 | ||
| B | Z | ||
| C | Z+1 |
Also, explain the following:
(i) Electron gain enthalpy of element A has large negative value than that of C.
(ii) Ionisation enthalpy of element C is less than that of A.
(iii) Electron gain enthalpy of B is positive.
Define electronegativity. Explain the factors influencing electronegativity. How does it vary along periods and groups? what are its units?
Electronegativity: It may be defined as the relative tendency of an atom to attract the shared pair of electrons towards itself in a covalent bond. Greater the tendency of the atom to attract the shared pair of electrons, more will be its electronegativity. For example, a covalent bond A-B can be represented as:
A : B (If A is more electronegative than B)
A : B (If B is more electronegative than A)
Factors influencing electronegativity:
(i) The size of the atom: The smaller the size of the atom more will be the electronegativity.
(ii) Nuclear charge: Electronegativity of an element increases with the increase in the nuclear charge of its atom.
Variation of electronegativity along periods and groups : In general, electronegativity increases along a period due to the decrease in atomic size and decreases down the group due to increase in atomic size.
Units: Electronegativity represents only the comparative values and it has no specific units. F (halogen) is the most electronegative element (4 . 0) while Cs alkali metal is the least electronegative (0.70).
Short Answer TypeExplain giving various reasons for the variation of electronegativity along a period and along a group.
Long Answer TypeWhat is the basic difference between the terms electronegativity and electron gain enthalpy?
Short Answer TypeHow would you react to the statement that the electronegativity of N on Pauling scale is 3.0 in all the nitrogen compounds?
Long Answer TypeThe valence of representative elements is either equal to the number of valence electrons or eight minus the number. What is the basis of their rule?
Short Answer TypePredict the formulae of the stable binary compounds that would be formed by the following pairs of elements:
silicon and oxygen
Predict the formulae of the stable binary compounds that would be formed by the following pairs of elements:
aluminium and bromine
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