What are ionic bonds? Section 15-5.

WHAT ARE IONIC BONDS?

Section 15-5

In an atom, the number of protons

(+) equals the number of

electrons (-). This is a neutral atom.

When an atom gains electrons (becomes negative) or loses

electrons (becomes positive), it is called

an ion.

IONIC BONDNeutral Atoms

Charged Particles

IONIC BONDCompounds are held together by atomic bonds, either ionic or covalent. Ionic bonds involve the transfer of outer shell electrons from one element to another. The element giving up the electron becomes a positive ion

and the element accepting the electron becomes a negative ion. As a result, they are attracted to each

other because of opposite electrical charges. This force is what bonds the elements together in a compound.

IONIC BOND

Sodium gives 1 electron away and chlorine takes on

the electron. Na+ ion and Cl-

ions are formed.

Many compounds that contain ionic bonds are solid. A crystal lattice is

a solid which has a pattern of positive and

negative ions. The shape of a crystal depends on its crystal lattice. There

are 6 types of crystal lattices.

CRYSTALS

WHAT ARE COVALENT

BONDS?

Section 15-6

COVALENT BONDS

Compounds are held together by atomic bonds, either ionic or covalent. Most atoms do not have complete outer energy levels.

Covalent bonds involve the sharing of outer energy level electrons. Thus ions are not

formed, the atoms remain neutral.

COVALENT BOND

H has 1 electron and O has 8 electrons. So each H shares its 1 electron with O and O

shares 2 electrons with H, 1 to each.

Atoms complete outer energy levels

Electrons are lost or gained

Atoms form ions

Atoms complete outer energy levels

Electrons are shared

Atoms remain neutral

IONIC VS. COVALENT

Ionic compoundsCovalent

compounds