Ionic bonds form when oppositely charged ions combine in a ratio that results in no overall electrical charge. Cations form when atoms lose electrons to achieve a stable electron configuration like neon, while anions form when atoms gain electrons like argon. Common examples given are sodium (Na) losing an electron to form Na+ and chlorine (Cl) gaining an electron to form Cl-. These ions are attracted to each other and bond to form sodium chloride (NaCl) with no overall charge.

2. IONIC BOND
 Compounds formed by combining ions in such
a ratio that the compound possess no
electrical charge is known as ionic compound
and its bond is known as ionic bond.
 Ions are atoms with electric charge.
 Ions that have less electrons than protons in
them are said to have a net positive charge
and are called cations, whereas ions than
have more electrons than protons in them are
said to have a net negative charge and are
called anions.

3. POSITIVE ION
 When an atom of an element loses
electrons from its outermost shell, it forms
a positive ion.
 For example. Atomic number of sodium is
11 and so its electronic configuration is
(2,8,1).

4.  If the number of electrons in the outermost orbit
of an atom are 1, 2 or 3, the atom tends to lose
electrons and forms positive ions.
 Thus, Sodium atom will lose 1 electron in its
outermost orbit shell, form positive ion and
attain octet configuration 2,8 similar to that of
inert gas neon.

5. NEGATIVE ION
 When an atom of an element gains electrons
from its outermost shell, it forms a negative ion.
 For example. Atomic number of chlorine is 17
and so its electronic configuration is (2,8,7).

6.  If the number of electrons in the outermost orbit
of an atom are 5, 6 or 7, the atom tends to gain
electrons and forms negative ions.
 Thus, Chlorine atom will gain 1 electron in its
outermost orbit shell, form negative ion and
attain octet configuration 2,8,8 similar to that of
inert gas argon.

7. IONIC BOND IN NaCl
 When sodium and chlorine come in contact,
each Na atom gives up an electron to become
a Na+ ion and Cl atom gains one electron to
become a Cl- ion.
 So NaCl formed will have no net charge.

8.  NaCl is the common salt that we use daily. It is
in ionic form even in solid state.
 Ionic bond is formed is formed because of
strong attraction forces oppositely charged
ionic and closed electronic configuration
between Na+ and Cl.
 Na+ and Cl ions are attracted by their nucleus
and form ion pair Na+Cl-.

9. MAGNESIUM CHLORIDE
 Since Magnesium's atomic number is 12, its
electronic configuration is (2,8,2).
 Hence, Magnesium is placed in group 2 and
period 3.
 Magnesium has 2 valence electrons in it and
so it will tend to lose them, achieve octet
configuration of nearby inert gas and for
magnesium ion (Mg2+)

10.  On the other hand, two chlorine atoms (2,8,7)
will accept each of these electrons liberated by
magnesium and form two Cl- ions. Thus,
Chlorine will attain an octet configuration of
(2,8,8).

11. MAGNESIUM OXIDE
 Magnesium element (2,8,2) loses two electrons
and forms magnesium ions Mg2+ .
 Similarly, oxygen atom (2,6) gains two electrons
and forms oxide ions (O2-).
 When Mg2+ and O2- ions come near each other,
due to opposite electric charge and attraction, they
form ionic bond and rise to magnesium oxide
MgO.

12. CHARACTERISTICS OF ATOMS,
IONS AND MOLECULE
 Sodium metal is highly reactive. It easily reacts
with oxygen (O2) of the air and forms sodium
oxide (Na2O). Na2O further reacts with water
and gives sodium hydroxide (NaOH).
 Sodium metal is highly active because its
electronic configuration is (2,8,1) and so it has
tendency to lose one electron from its valence
orbit and thus form sodium ion (Na+).

13.  Na+ attracts chloride ion (Cl-) which has a
negative charge. Thus, Na+ and Cl- combine
and form NaCl.
 Even though individually Na+ and Cl- are
reactive and non-edible, when they combine by
bonding, they lose their original individual
properties and form NaCl i.e. common salt
which can be consumed without any harm.
 Thus, bonding alters the properties of
elements.

14. CRYSTAL STRUCTURE OF NaCl
 By looking at the center of structure, one can
see that the chloride (Cl-) ion is connected
with six positively charged sodium (Na+) ions.
 Similarly, we can have sodium (Na+) ion at
centre connected with six negatively charged
(Cl-) .
 Such a structure of NaCl is called lattice
structure.

16.  The ions are arranged in three dimensions and
so this structure is called a three dimensional
structure.
 It should be noted that more the energy
between the positive and negative ions, more
the energy will be released.
 More the energy is released, more stable the
structure becomes.
 Since Na+ and Cl- highly attract each other, the
energy of the crystal structure decreases and
stability increases.

17. PROPERTIES OF IONIC
COMPOUNDS

18. 1. Physical Nature
 Ionic compounds are obtained in solid form.
 Due to strong electrostatic forces between ions
having electric charges, ions are hard and
brittle.
 Due to repulsion of opposite ions in these
compounds and due to their brittle nature, they
easily break into small pieces on applying
pressure.

19. 2. Solubility
 If ionic substances are dissolved in polar
solvents such as water, the attraction between
the ions of the compound decreases. this
makes ionic substances soluble in polar
substances.
 But these compounds are insoluble in non-polar
organic solvents such as ether, carbon
tetrachloride, benzene, etc.
 Due to these reasons, ionic compound sodium
chloride (NaCl), easily dissolves in water but
not in carbon tetrachloride.

20. 3. Melting Point and boiling point
 Ionic compounds have crystalline structure.
 In crystal structures, positive and negative ions
are joined strongly through their interactive
attraction forces.
 As a result, more energy is required to break
the crystal structure.
 Hence, compounds have high melting and
boiling points.

21. 4. Electrical conductivity
 Ionic compounds are electrically neutral
because there are no unpaired electrons in the
positive ions in their crystal structure.
 Thus, ionic solid compounds are bad
conductor of electricity.
 But these compounds lose their neutral
characteristics in aqueous solutions and get
ionised. Hence, in aqueous or molten
solutions, ionic compounds conduct electricity.