CHEMICAL BONDING How do elements bond?
Objectives: • Identify the different ways an element bond. • Compare and contrast ionic and covalent bond. • Distinguish between compound and molecules.
Why it’s important? • Chemical Bonds join the atoms in the materials you use everyday.
Vocabulary: • Ion • Ionic bond • Covalent bond • Polar bond • Metallic bond • Molecule
Review: Valence Electrons • Valence electrons are the electrons in the highest (last outer energy) occupied energy level of the atom. • Valence electrons are the only electrons generally involved in bond formation.
What is an ion? • Atom or molecule that is no longer neutral since it has lost or gained an electron.
Define Chemical Bonding? • Elements that do not have a complete energy level, tend to react. • When the elements react, chemical bonds are formed.
How do atoms bond? • Atoms form bonds with other atoms using electrons in their outer energy level.
What are the different ways atoms bond? • Gain Electron (+) • Lose Electron (-) • Pooling Electron (together) • Sharing Electron
1. Ionic Bond: • Chemical bonding holding oppositely charged ions together. • Between a metal and non metal • Responsible for gaining or losing electrons.
A Positive Ion (Cation): • An atom that has lost one or more electrons. • + charge
A Negative Ion (Anion) • An atom that has gained one or more electrons. • Negatively (-) charged.
2. Covalent Bonding: • Share Electrons. • Bond that forms between non metals only. • Produce molecular compounds. • Ex. Hydrogen Molecule
2 Forms: • Double Bond: when 2 pairs of electrons are shared. • Triple Bond: when 3 pairs of electrons are shared.
3. Metallic Bonding: • Bond between metal and another metal. • Electrons in the outer energy level are not tightly held together----move freely (pooled) • Electrons stick together • Responsible for good conductivity, malleability and ductility.
4. Polar Bond: • Bond in which electrons are shared unevenly. • Ex. Water
Video • https://youtu.be/ljvX-RMv_lw