CHAPTER 1: MATTER AND CHANGE

1. CHAPTER 1:MATTER AND CHANGE General Chemistry

2. Elements

4. Groups and Periods Group: • Vertical column • Elements with similar chemical properties Period: • Horizontal row • Physical and chemical properties change regularly across a period

5. Metals METAL: an element that is a good conductor of heat and electricity • Shiny (metallic luster) • Most are solid at room temperature • Malleable (can be hammered or rolled into thin sheets) • Ductile (can be drawn into wire) • Classifications – alkali metals, alkaline earth metals, transition metals, other metals

7. Nonmetals NONMETAL: an element that is a poor conductor of heat and electricity • Many are gases at room temperature (Ex: N, O, F, Cl, etc.) • Many are solids at room temperature (Ex: C, P, Se, S, I, etc.) • Solids are brittle (NOT malleable or ductile) • Classifications – halogens, noble gases, other nonmetals

9. Noble Gases • Unreactive • All are gases at room temperature

10. Metalloids METALLOID: an element that has some characteristics of metals and some characteristics of nonmetals • All are solid at room temperature • Less malleable than metals, but not as brittle as nonmetals • Also known as semiconductors

12. Building Blocks of Matter • Matter – Anything that takes up space and has mass • Mass – Measure of amount of matter (grams) • Atom – Smallest part of an element that maintains the properties of that element • Element – Pure substance with only one type of atom • Compound – Pure substance, atoms of two or more elements are chemically bonded

13. Classification of matter Homogeneous mixture Heterogeneous mixture Compound Element milk sand soda Kool-aid blood phosphorus salt bones baking soda quartz paper

15. Properties of matter Property – an attribute or quality of a substance; used to describe a substance • Chemical Property • Relates to substance’s ability to undergo changes to become different substances • Describes how a substance changes identity • Examples: • Ability to burn • Ability to rust • Does not react with… • Reacts with… • Physical Property • Observed or measured without changing identity of a substance • Describes substance itself (NOT how it changes) • Examples: • Color • Boiling point • Melting point • Conductivity • Density

16. Types of Change • Physical Change • A change in a substance that does NOT involve a change in identity • substance keeps the same composition • Examples: • Ripping paper • Sanding wood • Making a hole • Shattering glass • Solid ↔liquid ↔ gas (Change of state) • Chemical Change (Reaction) • One or more substances is converted into a new substance with a different composition • Chemical identity changes • Chemical bonds broken and/or formed • Examples: • Burning paper • Baking soda/vinegar • Burning magnesium • 2Mg (s) + O2 (g)  2MgO (s) • Sodium carbonate + calcium chloride • Na2CO3 (aq) + CaCl2 (aq)  2NaCl (aq) + CaCO3 (s)

17. Evidence of a chemical reaction (change) • Energy (light/heat) • Color change • Bubbles (formation of gas) • Formation of a precipitate (solid from solution)

19. Chemical Equations: Words to Know: • Reactants – Anything on left side of arrow • Products – anything on right side of arrow • Coefficient – Large number in front of substance • Subscript – Small number after an element symbol 2Mg (s) + O2 (g)  2MgO (s)

20. To Balance an Equation: 1. Total numbers of each element for both sides 2. Check if each element is the same on both sides 3. Change the total on the inventory list so that the element matches. 4. Add a coefficient to the substance in the equation 5. Adjust the inventory list to reflect any changes in other atoms 6. Move on to each atom until the lists match for EVERY element Never change SUBSCRIPTS in Balancing!!