Page 145 - Science Course 2 (Book 1)

Mo.5-L3a: What is Ionic Bonding?

Metal atoms, such as sodium, become more stable Atoms are electrically neutral because they have the
when they lose valence electrons and form a same number of protons and electrons.
chemical bond with a nonmetal.
Once an atom gains or loses electrons, it becomes a
Neutral Atoms Negative Ion charged ion.

Positive Ion

Sodium atoms have a tendency to lose a valence
electron. Chlorine atoms have a tendency to gain a
valence electron. Ionic Bonds—Electron Transferring
When forming a compound, the nonmetal atoms
A sodium atom has 1 Losing 1 valence gain the electrons lost by the metal atoms.
valence electron. If it electron gives sodium
loses its 1 valence a positive charge. It now The attraction between positively and negatively
electron, its next outer has the electron charged ions in an ionic compound is an ionic bond.
level will have 8 arrangement of neon(Ne)
electrons and is stable.

Neutral (+)
Na Cl

An ionic bond forms between Na and Cl when an Na
atom transfers an electron to a Cl atom.
Unstable Atom Stable Ion
7 electron 7 electron
8 electrons 8 electrons
A chlorine atom has 7 Gaining 1 electron gives 2 electrons 2 electrons
valence electrons. If it the chlorine atom a
gains 1electron its negative charge. It now
outer energy level will has the electron
have 8 electrons arrangement of argon
(Ar) and is stable.
Neutral (–)

Sodium and chlorine atoms are stable when they
have eight valence electron. Sodium atoms lose
one valence electron and become stable.
Chlorine atoms gain one valence electron and
become stable.
Unstable Atom Stable Ion

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