September 9, 2013 Notes

The Chemistry of Matter Review Notes

I.                Atoms:  The Building blocks of Matter

A.     Matter and Energy

1.     Matter is anything that has mass and volume

a.     Occurs in three states:  solid, liquid, gas

b.     Physical change-change in state

c.     Chemical change-change in chemical composition; involves making and breaking of chemical bonds

2.     Energy is the Ability to do work

a.     Kinetic – energy in motion

b.     Potential –energy at rest

B.     Elements, Atoms, and Their Properties

1.     Elements are substances that can’t be chemically changed into simpler substances

2.     Atoms are the smallest parts of an element that have the properties of the element

a.     Nucleus = protons (+) and neutrons (neutral)

3.     Atomic number = # of protons; will also equal the number of electrons in an uncharged atom

4.     Atomic mass = # protons + # neutrons

5.     Isotopes are elements with the same atomic number but different atomic masses due to a different number of neutrons; radioactive isotopes throw off particles when their nuclei break down

6.     Ions are atoms with a charge because they have gained or lost electrons

II.              Molecules, Compounds, Bonds

A.  Molecule – group of two or more atoms held together by bonds

B. Compound – two or more bonded elements

C. Chemical formula – shows the kind and number of atoms in a compound (ex. CO₂)

D. Structural formula – shows the kind, number, and arrangement of atoms in a compound (ex. C=O)

E. Bonds form when two or more atoms are attracted to each other. The type of bond formed is based on the number of valence electrons.

                  1. Covalent bonds – atoms share electrons

a. double, single and triple bonds – refers to number of electron pairs that are shared

                                    b. polar bonds – electrons not shared equally

2. Ionic Bonds result when electrons are transferred between elements resulting in ions

F.  Mixtures and Solutions

                  1.  Mixture – two substances not chemically combined

                  2.  Solution – mixture in which components are uniformly distributed

3.  Solvent – substance which dissolves; water is called the “universal solvent” because it dissolves so many substances

4. Solute – substance being dissolved

G. Acids and Bases: measured on pH scale

                  1.  Acid – releases hydrogen ions (H⁺) in solution; pH < 7

                  2. Neutral – pH 7

                  3. Base (alkaline) – releases hydroxide ions (OH-) in solution; pH >7

Atoms, Isotopes, Ions, Molecules

Matter- Everything has matter that takes up space/and or has mass

Elements- Types of matter that make up Molecules and have physical and chemical properties. There are 118 Elements but only 92 occur naturally. Oxygen, Carbon, Hydrogen, and Nitrogen are necessary for living

Atom- The smallest unit of matter that make up elements 

• Nucleus- The center of the atom, containing protons and neutrons
• Outer Region- Contains the electrons that orbit the nucleus
• Proton- Positively charged 
• Neutron- No charge
• Electron - Much smaller, and has a negative charge

Atomic Number- The number of protons determines the element's atomic number

Mass Number- The number of protons and neutrons determines the element's mass number. It can help determine the amount of neutrons by subtracting the protons from the number.

Atomic Mass- The mass of the element we see most often in nature

Radioisotopes- Isotopes that emit protons, neutrons, or electrons in order to become more stable