Chemistry in 7 Days The basic unit of chemistry is the atom The atom has protons and neutrons in the...
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Transcript of Chemistry in 7 Days The basic unit of chemistry is the atom The atom has protons and neutrons in the...
Chemistry in 7 Days
• The basic unit of chemistry is the atom
• The atom has protons and neutrons in the nucleus and electrons orbiting the nucleus.
• Electrons have a negative charge, protons positive, and neutrons are neutral
Add Illustration of atom
Atoms
• The number of protons and the number of electrons should equal each other, or you have an ion with a charge (+ or -)
Pic of ion
Elements
• Elements are atoms with the same number of protons. Because they have the same number of protons and electrons they have the same chemical characteristics
• Isotopes are atoms with differing numbers of neutrons. They are the same chemically
Lab
• Lab 5A, p 47, inside the atom
Periodic table
• The periodic table is an orderly arrangement of the elements based on the number of protons in the atoms of that element.
• This is known as the atomic number
• A period is a row across the table
• A group or family is a column up and down the table
Groups and families
• Groups and families have similar characteristics because they have the same number of electrons in the outer level (they look the same to other atoms)
Periods
• Periods, the rows across the periodic table, have the same number of electron orbitals or shells or levels
Lab 6C
• P 57, Valence
Pic of electron orbitals
Joining atoms
• Ionic bonds- one atom takes electrons from the other. They have positive and negative charges and stick together like magnets.
• Covalent bonds-They share electrons
• Both types of bond are an attempt to have a full outer level of electrons. That’s how atoms are most stable.
Pics of ionic and covalent bonds
Naming chemical compounds
• Systematic Nomenclature:
• For names start with element to the left side on the periodic table
• add -ide to the second element
More Naming
• use Greek prefixes for number of atoms: mono, di, tri, tetra, penta, hexa, hepta, octa, nona, deca
• Example:
• CO carbon monoxide
• CO2 carbon dioxide
• N2O5 dinitrogen pentoxide
Physical and chemical change
• Physical change-substance is the same
• Chemical change- a new substance (chemical) is formed
Physical Change
• Lab 4A , p 37, Phase changes of water
Essay Questions
• Thoroughly explain why the members of the same groups and families on the periodic table react in a similar manner.
• What is the difference between an ionic bond and a covalent bond?
Chemical Equations
• Equations are a representation of a chemical reaction
• 2H2 + O2 = 2H2O
• The numbers of atoms of each type must be the same on each side
• Start by balancing an element that appears in only one reactant and product.
• Once one element is balanced, proceed to balance another, and another, until all elements are balanced.
• Balance chemical formulas by placing coefficients in front of them. Do not add subscripts, because this will change the formulas.
Try this one
• 1. CH4 + O2 ->CO2 + H2O
Did you get this?
• 1. 1 CH4 + 2 O2 1 CO2 + 2 H2O
Water and Solutions
• Water is very important in chemistry
• It enables chemicals to react with each other
• It is so important is almost a science on its own
• So why is water so important in so many chemical reactions?
Water
• Unique polar molecule, it is the universal solvent
• Dissolved in a liquid, molecules can move much more freely than as a solid
Acids and Bases
• Acids – Force an “H-” on a substance• Bases – Rip an “H-” from a substance• pH = the negative log of the hydronium ion
(H3O+) concentration• pH scale from 0 to 14• 0 is very strong acid, 14 very strong base, 7
is neutral• Each number is a factor of 10 from the next
Solutions
• Concentration vs dilution
• Do a serial dilution in SEPUP tray
• Lab 9B, Solutions and Beer’s Law, p 69
pH scale
• Lab 13 A p101
• Serial dilution in SEPUP tray
Electro Chemistry
• Works in solutions and with ions
• Lab 15B, p 124