What You Should Already Know Chemistry What You Should Already Know

Matter Matter is defined as anything that has mass and volume. Matter can be divided into two main groups: mixture and pure substance. ALL matter is made of atoms.

Mixtures Mixture Separation Techniques Two or more types of pure substances NOT chemically combined No definite ratio Can be heterogeneous or homogeneous Substances retain their original chemical and physical properties Separated using physical properties Sort by size, shape, or color Remove portions with magnets Fractional distillation Evaporation Decant Chromatography Filtration precipitation

Pure Substances Elements Compounds About 110 known at this point Organized on the Periodic Table Made of atoms Each type of element has a unique atomic structure Basic structure includes p+, n, and e- CHEMICAL combinations of two or more elements Combined in definite, whole # ratios Made or separated only through chemical reactions Simply classified as ionic or covalent Have completely different properties than the elements that make them

Basic Atomic Structure Atoms are made of protons, neutrons, and electrons. An ION is an atom that has lost or gained electrons. Ions can be positive or negatively charged. An ISOTOPE is an atom with a different number of neutrons than most other atoms of that type.

Subatomic Particles Proton Found in nucleus Positive charge (+1) Mass = 1amu # in nucleus identifies atomic # Neutron Neutral charge Number in nucleus can change without atom type changing Electron Found in energy levels around the nucleus Negative charge (-1) Mass = 0amu Outer shell #e- can change to make ions

Different Types of Atoms Atoms are all made of subatomic particles but there are several different types of atoms The number of subatomic particles in each atom will determine the type of atom The # OF PROTONS will be unique for each type of atom. This is the atomic number. The periodic table of elements is the best tool for chemistry. You should ALWAYS have one ready to use.

Basic Periodic Table Information Nearly every periodic table will have the same basic information. Usually this includes symbol, name, atomic number, and average atomic mass.

Using the Periodic Table You should already know how to use the periodic table to identify basic information related to atoms. Number of p+ is the atomic number Number of e- is the same as the atomic number for neutral atoms Number of neutrons = mass number – atomic number