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?
What is the importance of electronegativity?
1. Electronegativity can be used to predict the nature of bonds between two atoms.
(i) If the two atoms are identical and have high electronegativity then the bond between them is called non-polar covalent bond or purely covalent bond. For example, H2 (or H-H), Cl2 (or Cl - Cl).
(ii) If the two atoms are dissimilar and have high electronegativity, then the bond between them is called a polar covalent bond. For example H -Br. Li—Cl etc.
2. Electronegativity helps us in predicting the polarity of covalent bonds.
(i) The greater the electronegativity difference between the two bonded atoms, the greater is the polarity of the covalent bond. For example, a bond between H and Cl is more polar (electronegativity difference = 0.9) than the bond between Br and CI (electronegativity difference = 0.2).
(ii) If the two atoms are dissimilar and have a large difference in their electronegativity,then the bond between them is called an electrovalent bond (or ionic bond).
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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