Chemistry note set II / Quiz FC - 3

Explain the OCTET rule

An element is stable with 8 valence electrons *not all

What do compounds allow elements to do?

become more stable

Compounds that are extremely unstable will break down to form the more stable

smaller parts

Elements tend to join chemically to get

8 valence electrons

How do mixtures form

Mixtures form by physically junking (combining) 2 or more substances together

The formation of a mixture is not a result of lowering energy

Why do chemical reactions form

They occur to produce a more stable product than the existing

reactants

How do you know when a chemical reaction occurs?

1. Evolution of a ____gas___

2. Evolution of ________light____

3. Evolution of ________heat___

4. Color change

5. Evolution of a __________precipitate__

What is a precipitate?

Precipitate: an insoluble substance that is produced as a result of a chemical reaction

What are valence electrons

the electrons in an atom’s outermost shell (the valence shell), and they help determine how the atom bonds and reacts chemically.