Exercises
Chemical Bonding: Basic Ideas
*01.What type of force is responsible for chemical bonding?
Explain the differences between ionic bonding and cova-
lent bonding.
*02.What kind of bonding (ionic or covalent) would you
predict for the products resulting from the following com-
binations of elements?
(a) NaCl 2 ; (c) N 2 O 2 ,
(b) CO 2 ; (d) SO 2.
*03.Why are covalent bonds called directional bonds, whereas
ionic bonding is termed nondirectional?
*04.(a) What do Lewis dot formulas for atoms show? (b) Write
Lewis dot formulas for the following atoms: He; Si; P; Ne;
Mg; Br.
*05.Write Lewis dot formulas for the following atoms: Li; B;
As; K; Xe; Al.
*06.Describe the types of bonding in sodium chlorate, NaClO 3.O
O OO
Na Cl*07.Describe the types of bonding in ammonium chloride,
NH 4 Cl.*08.Based on the positions in the periodic table of the follow-
ing pairs of elements, predict whether bonding between
the two would be primarily ionic or covalent. Justify your
answers. (a) Ca and Cl; (b) P and O; (c) Br and I; (d) Li
and I; (e) Si and Br; (f) Ba and F.
*09.Predict whether the bonding between the following pairs
of elements would be primarily ionic or covalent. Justify
your answers. (a) Rb and Cl; (b) N and O; (c) Ca and F;
(d) P and S; (e) C and F; (f) K and O.
*10.Classify the following compounds as ionic or covalent:
(a) Ca(NO 3 ) 2 ; (b) H 2 S; (c) KNO 3 ; (d) CaCl 2 ; (e) H 2 CO 3 ;
(f) PCl 3 ; (g) Li 2 O; (h) N 2 H 4 ; (i) SOCl 2.HHH NClH 300 CHAPTER 7: Chemical Bonding
Delocalization of electrons Refers to bonding electrons dis-
tributed among more than two atoms that are bonded together;
occurs in species that exhibit resonance.
Dipole Refers to the separation of charge between two cova-
lently bonded atoms.
Dipole moment ( ) The product of the distance separating
opposite charges of equal magnitude and the magnitude of the
charge; a measure of the polarity of a bond or molecule. A mea-
sured dipole moment refers to the dipole moment of an entire
molecule.
Double bond A covalent bond resulting from the sharing of four
electrons (two pairs) between two atoms.
Electron-deficient compound A compound containing at
least one atom (other than H) that shares fewer than eight
electrons.
Formal charge The hypothetical charge on an atom in a cova-
lently bonded molecule or ion; bonding electrons are counted
as though they were shared equally between the two bonded
atoms.
Heteronuclear Consisting of different elements.
Homonuclear Consisting of only one element.
Ion An atom or a group of atoms that carries an electrical
charge.
Ionic bonding The attraction of oppositely charged ions (cations
and anions) in large numbers to form a solid. Ions result from
the transfer of one or more electrons from one atom or group
of atoms to another.
Ionic compound A compound containing predominantly ionic
bonding.
Isoelectronic Having the same number of electrons.
Lewis acid A substance that accepts a share in a pair of electrons
from another species.
Lewis base A substance that makes available a share in an elec-
tron pair.
Lewis formula The representation of a molecule, ion, or for-
mula unit by showing atomic symbols and only outer-shell
electrons; does not represent the shape of the molecule or ion.
Lone pair A pair of electrons residing on one atom and not
shared by other atoms; unshared pair.
Monatomic ion An ion that consists of only one atom.
Nonpolar bond A covalent bond between two atoms with the
same electronegativity, so that the electron density is symmet-
rically distributed.
Octet rule Many representative elements attain at least a share
of eight electrons in their valence shells when they form mol-
ecular or ionic compounds; there are some limitations.
Polar bond A covalent bond between two atoms with different
electronegativities, so that the electron density is unsymmetri-
cally distributed.
Polyatomic ion An ion that consists of more than one atom.
Resonance A concept in which two or more Lewis formulas for
the same arrangement of atoms (resonance structures) are used
to describe the bonding in a molecule or ion.
Single bond A covalent bond resulting from the sharing of two
electrons (one pair) between two atoms.
Triple bond A covalent bond resulting from the sharing of six
electrons (three pairs) between two atoms.
Unshared pair See Lone pair.
Valence electrons The sand pelectrons in the outermost shell
of an atom.