Chapter 3 Classification of Matter Objectives: Define and give examples of 3 states of matter (3.1 & 3.2) Distinguish between substances and mixtures (3.3 & 3.12) Understand what elements are (3.4-3.7) Distinguish between metals, nonmetals and metalloids (3.8) Define compounds and diatomic molecules (3.9 & 3.10) Be able to write chemical formulas (3.11)

What is Matter? Anything that has mass and occupies space Composed of atoms Exists in three states on earth Exists in fourth state in space

Solids Definite Particles tightly packed Crystalline – Amorphous solids –

Liquids Definite volume Not a Particles have Particles can

Gases Indefinite volume No Particles have Particles

Substances and Mixtures Pure Substance: a particular kind of matter with a definite, fixed composition Mixture:

Matter Pure substances (homogeneous composition) Mixtures of two or more substances Elements Compounds Solutions (homogeneous composition – one phase) Heterogeneous mixtures (two or more phases) Figure 3.2 (page 48)

Types of Mixtures Heterogeneous mixtures Homogeneous mixtures Chocolate chip cookies; granite Homogeneous mixtures

Separating Mixtures Do NOT cause chemical changes Heterogeneous Mixtures

Separating Mixtures Homogeneous Mixtures

Separating Mixtures Homogeneous Mixtures

Separating Mixtures Homogeneous Mixtures

Pure Substances Elements Compound

Elements ~111 presently known elements At room temperature: Figure 3.3 – distribution of elements in the

Elements Names of the elements Greek Latin Location where discovered

Elements Arranged in the Periodic Table (inside front cover) Symbols Some symbols are Latin/Greek name (Table 3.4)

Elements Classification Metal Nonmetal Metalloid See Table 3.5

Elements Metals: Usually solid at room temperature High luster Malleable Usually don’t combine with each other

Elements Nonmetals: Solids ( ); Liquid ( ); Gases (all others) Poor conductors Low melting point; Will combine Some found uncombined in nature

Elements Metalloids Have properties of Some used for semiconductors in electronics

Compounds Two or more elements New properties Can be chemically separated

Compounds Molecular Held together with Molecule: Water is an example

Compounds Ionic Ion: Cation – Anion – Held together by ionic bond –

Compounds Diatomic Molecules Always only 2 atoms 7 naturally occurring

Chemical Formulas Abbreviations for compounds Sodium Chloride (NaCl)

Chemical Formulas Subscript indicates # of atoms present H2O has 2 Hydrogen atoms and 1 Oxygen atom NaOH has

Chemical Formulas Parentheses are used to show when a compound contains more than one group of atoms that occurs as a unit

Chemical Formulas Show only number and kind of atom Do not show arrangement of the atoms or how chemically bonded