What are Chemical bonds? Chemical bonds are formed between atoms when their electrons interact. Electrons: Small Negatively charged Surround the nucleus

How are Chemical bonds formed? Chemical bonds involve the transfer or sharing of electrons between two atoms Ionic bonds involve transfer of electrons from one atom to another Covalent bonds involve sharing of electrons between two atoms

Ionic vs Covalent Bonds Ionic bond form when one atom loses electrons and another atom gains electrons. The atom that loses electrons becomes a positive “ion” The atom that gains electrons becomes a negative “ion The bond is formed by the attraction between the two oppositely charged ions Covalent bond forms when two atoms share electrons. The bond is formed by the mutual attraction for the shared electrons

Ionic Bonds Ionic compounds form when atoms transfer electrons The bond is the attraction between the positive sodium ion (cation) and the negative chloride ion (anion)

Covalent Bonds Covalent compounds form The bond is the mutual attraction for the shared pair of electrons

Why do atoms form bonds? Atoms gain/lose or share electrons to attain a specific number of electrons in their outer shell This number is called an octet Atoms form bonds to attain an octet

An Octet An octet Is a filled outer shell (also called valence shell) Is eight electrons (except period 1 which only has two)

What is special about an Octet? The octet Having an octet in the outer shell makes the atom very stable This is the same number of electrons that are in the outer shell of the noble gases That is what makes noble gases stable (non reactive)

The Octet Rule The octet rule states that atoms gain/lose or share electrons to attain noble gas arrangement in their outer (valence shell) Noble Gas valence electrons He 2 Ne 8 Ar 8 Kr 8

Ionic bonds - atoms transfer electrons Form when one atom is willing to give up and electron to attain an octet (metal). And another atom requires and electron to form an octet (non metal) Covalent bonds - atoms share electrons Form when both atoms require electrons to attain an octet but neither is willing to give one up – so they share (both non metals) What determines an Ionic vs Covalent Bond?

Ionic vs Covalent Bonds Ionic bonds form between a metal (blue) and a non metals (yellow) Covalent bonds form between two non metals (yellow)

Ionic Bonds Ionic compounds form when atoms transfer electrons to complete octets between metals and nonmetals The bond is the attraction between the positive sodium ion (cation) and the negative chloride ion (anion)

Covalent Bonds Covalent compounds form when atoms share electrons to complete octet Between two nonmetals The bond is the mutual attraction for the shared pair of electrons