Chemistry
Define or explain the terms:
(i) Covalent or molecular bond
(ii) Covalent or molecular compound
(iii) Covalency
(iv) Shared pair of electrons.
Answer
(i) Covalent or molecular bond — The chemical bond that is formed between two combining atoms by mutual sharing of one or more pair of electrons is called a covalent bond.
Depending on the number of electron pairs shared : bond is single [-], double [=], or triple [≡] covalent.
(ii) Covalent or molecular compound — The chemical compound formed due to the mutual sharing of electrons between the given pair of atoms thereby forming a covalent bond is called covalent compound.
(iii) Covalency — Covalency of an atom is the number of electron pairs which the atom shares with one or more atoms of the same or different kind to achieve stable electronic configuration. For example : the covalency of hydrogen is 1, oxygen is 2 and nitrogen is 3.
(iv) Shared pair of electrons — A pair of electrons which is being shared between two atoms resulting in the formation of a covalent bond is called a shared pair of electrons.
Related Questions
Give two differences between the covalent compounds – methane (non-polar) and HCl (polar)
Explain with the help of electron dot diagrams the formation of the following molecules, stating the valency of each element involved.
(a) Hydrogen
(b) Chlorine
(c) Oxygen
(d) Nitrogen
(e) Water
(f) Methane
(g) Carbon tetrachloride
(h) Ammonia
(i) Carbon dioxide
[at. nos. H = 1, C = 6, N = 7, O = 8, Cl = 17]
Fill in the blanks with appropriate word/s from the brackets :
NaCl an electrovalent compound is formed as a result of transfer of …………… (one, two, three) valence electrons from metallic sodium to non-metallic chlorine atom. CaO is similarly formed as a result of transfer of …………… (one, two, three) valence electron/s from metallic calcium to non-metallic oxygen and magnesium chloride by transfer of …………… (one, two, three) valence electron/s from …………… (one, two) magnesium atom/s to …………… (one, two) chlorine atom/s.
Fill in the blanks with appropriate word/s from the brackets :
Covalent compounds are formed by sharing electron pairs between non-metallic atoms. Non-metallic atoms having …………… , …………… , …………… valence electrons (4, 5, 6, 7) share one, two or three pairs of electrons respectively.