Chemical Bonding

Chemical Bonding

1Elements are made of only one kind of atom. Example: Cu AlWhen two or more elements combine chemically, a compound is formed. Example: NaCl H2O

2Elements

Aluminum Potassium SulfateAlK(SO4)2

Sodium BicarbonateNaHCO3

Zinc OxideZnO

Cupric SulfateCuSO4

Atoms must form bonds between them to form compounds.

8Atoms use their valence electrons to form bonds.Valence electrons are the electrons in an atoms last energy level9Sodium

chlorine

You can determine valence electrons by determining the group the element belongs to. (Subtract 10 from groups 13 18 to determine valence electrons.)

12An atom with fewer than 8 valence electrons is more likely to form bonds.

13Atoms use the magic number 8 to make their outer energy levels stable. (Except for H and He. Their magic number is 2.)

14Atoms of elements in group 18 dont usually form compounds because they already have 8 valence electrons. (Helium either because its outer energy level only holds two electrons and thats how many it has.)

15Noble Gases

Two kinds of chemical bonds:

17Ionic bonds

18 form when an atom loses or gains electrons from a nearby atom

the oppositely charged ions are attracted to each other

19Ionic bonds usually form between a metal and a nonmetalthe new compounds formed are called ionic compounds

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Covalent bonds22 A covalent bond is formed when atoms share electrons to reach the magic number 8 in their outer energy level23Covalent bonds usually form between two nonmetals.

Covalent compounds are made of individual particles called molecules

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