6 Elements A substance that consists only of atoms with the same atomic number. Chemical Symbol: A collection of 1 or 2 letters used to represent an element. First chemical symbols were assigned by John Dalton in 1803 (no longer in use) Some modern chemical symbols: Hg, Zn, Mg
7 John Dalton
9 John Dalton’s Symbols
10 John Dalton’s Symbols
11 Chemistry and the Elements
13 Elements and the Periodic Table Periods: The seven horizontal rows that group elements based on their principal quantum number. Groups: The 18 vertical columns that group elements based on their angular momentum quantum number.
14 Elements and the Periodic Table
15 Elements and the Periodic Table Main Groups: s-block elements: Two groups on the left (1 & 2) p-block elements: Six groups on the right (13–18) Transition Metal Groups: d-block elements: Ten groups in the middle (3–12) f-block elements: Fourteen groups between 3 & 4 are called inner transition metals.
16 Elements and the Periodic Table
17 Elements and the Periodic Table
23 Properties of Matter Matter: anything that has both mass & volume. Properties: describe or identify matter. Intensive Properties do not depend on amount. Extensive Properties do depend on amount.
24 Physical Properties can be determined without changing the chemical makeup of the sample. Some typical physical properties are: Melting Point, Boiling Point, Density, Mass, Touch, Taste, Temperature, Size, Color, Hardness, Conductivity. Some typical physical changes are: Melting, Freezing, Boiling, Condensation, Evaporation, Dissolving, Stretching, Bending, Breaking. Properties of Matter
25 Chemical Properties are those that do change the chemical makeup of the sample. Some typical chemical properties are: Burning, Cooking, Rusting, Color change, Souring of milk, Ripening of fruit, Browning of apples, Taking a photograph, Digesting food. Note: Chemical properties are actually chemical changes. Properties of Matter
26 List of chemical changes possible. Description by senses – shape, color, odor, etc. Measurable properties – density, boiling point, etc. PROPERTIES Old substance destroyed. New substance formed. New form of old substance. No new substances formed. CHANGE CHEMICALPHYSICAL Properties of Matter
27 Properties of Matter
28 Properties of Matter Homogeneous matter has the same appearance, composition, and properties throughout. Heterogeneous matter has visibly different phases which can be seen, or properties that vary through the substance.
29 Pure substances have a distinct set of physical and chemical properties and cannot be separated by physical changes. A mixture is two or more pure substances that can be separated by physical changes. Properties of Matter
30 An element is a pure substance with its own set of physical and chemical properties that cannot be decomposed into simpler substances. A compound is a pure substance that can be decomposed by a chemical change into two or more pure substances. Properties of Matter
31 Matter Classification: Matter can be subdivided into mixtures and pure substances. Properties of Matter
32 Mixture Video
33 Properties of Matter
34 Metals: Found on left side of periodic table. Nonmetals: Found on the right side of periodic table. Semimetals: Form a zigzag line at the boundary between metals and nonmetals. Properties of Matter
35 Which of the following represents a mixture? Properties of Matter
36 If the red spheres are oxygen and the white are hydrogen, which of the following represents (a) hydrogen peroxide, (b) hydroxide ions, and (c) a mixture of hydrogen and oxygen gas? Properties of Matter