Download 2 Types of Chemical Bonds

Unit 4:
Bonds, Formulas & Names
Chemical Bonding
• A chemical bond is formed when atoms
of elements change the number of
valence electrons they have to get 8 or 2
• A chemical bond combines elements
together to form a compound!
2 Types of Chemical Bonds
1. Ionic Bond – gain or lose valence electrons
• This is a chemical bond formed by the attraction between positive
(+) and negative (-) ions.
What types of elements form Ionic Bonds?
Metal elements:
• Lose valence electrons to form (+) ions
• Easier to lose than gain to get 8
Non Metal elements:
• Gain valence electrons to form (-) ions
• Easier to gain than lose to get 8
For example: Sodium (Na) and Chlorine (Cl) form an Ionic bond
2 Types of Chemical Bonds
2. Covalent Bond – share valence electrons
• This is a chemical bond formed by the sharing valence electrons
between 2 atoms
What type of element forms Covalent bonds?
Non Metal elements:
• Neither atom wants to lose an electron
• Both atoms have high ionization energy
For example: Hydrogen and Chlorine form a covalent bond
Physical Bonds
Metallic Bond
• This is a Physical Bond formed between metal elements.
• Electrons flow freely in a “sea of electrons” surrounding their positive
nuclei.
What type of element forms Metallic Bonds?
Metal elements
• A metallic bond does NOT produce a compound
• The metallic bond gives metals malleability and great conductivity!
*Metal video?*
2 Types of Covalent bonds
Things to remember:
• A covalent bond is a shared pair of electrons between 2 non-metal
elements
• Each element will not share the electrons equally (due to different
electronegativity)
1.
Polar Covalent = Valence electrons NOT shared equally
** Use delta (
2.
δ) to indicate partial charge
Non-Polar Covalent = Valence electrons shared equally
• Dr. HOFBrINCl
Examples:
Hydrogen & Fluorine form a Polar Covalent bond
Molecular Fluorine forms a Non Polar Covalent bond
Polar or nonpolar Covalent? Ionic? How to tell?
• Type(s) of element(s) combining together
o Metal + Non metal
o Non metal + Non metal
o Same Non metal?
• Difference in Electronegativity
Electronegativity Difference
≤ 0.4
between 0.4 and 1.7
≥ 1.7
Bond Type
nonpolar covalent
polar covalent
ionic