Chemical Bonding Chapter 5.2

2 Types of Chemical Bonds 1.Ionic Bonds – gain/lose electrons 2.Covalent Bonds – “sharing” 3.Metallic Bonds – “sea of electrons”

3 Chemical Bonding Whether atoms will interact depends almost entirely on: 1.The arrangement of their outer energy level electrons (valence electrons). 2.Strength of attractive force between protons and electrons.

4 Ionic Bonds Electrons are transferred between atoms. Metal and Nonmetal – One atom gains electrons – Other atom loses electrons. Each atom becomes an ion. Ionic Bonding Clip Ionic Bonding NaCl

Why are Ionic Bonds so strong? Anions (- ions) and cations (+ ions) are held together by opposite charges. – electrostatic attraction(force). – Occurs between all the ions

6 Types of Chemical Bonds 1.Ionic Bonds – gain/lose electrons 2.Covalent Bonds – “sharing” 3.Metallic Bonds – “sea of electrons”

7 Covalent Bonds Electrons are shared between atoms. – Atoms that do not lose electrons easily usually form covalent bonds. Occurs between 2 nonmetals. The attraction between both nuclei and the shared electrons hold the atoms together in a covalent bond.

Covalent bonding l Fluorine has seven valence electrons l A second atom also has seven l By sharing electrons l Both end up with full orbitals FF 8 Valence electrons Bonding Pair of electrons Lone Pair of electrons

Polar vs non Polar covalent l Covalent means to share valence e- l If both atoms do not share the electrons equally it is said to be Polar. Example water l If both atoms share the electrons equally they are non-Polar. Example carbon dioxide. O C O

10 Types of Chemical Bonds 1.Ionic Bonds – gain/lose electrons 2.Covalent Bonds – “sharing” 3.Metallic Bonds – “sea of electrons”

Metallic Bonds Metal - Metal compounds Metals hold onto their valence electrons very weakly. Therefore the electrons can flow between multiple atom nuclei. Positive ions surrounded by a sea of electrons

Polyatomic ions Are groups of covalently bonded atoms that are still not happy. Example: (OH - )which is still missing a electron for everyone to be happy. Two or more atoms grouped in parentheses. [ Na(OH - ) ] They cannot be separated.