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.

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