ATOMS The beginning of matter
What is an atom? An atom is the smallest unit of matter that exists.
What is matter? Matter is anything that has mass (weight) and occupies space (volume).
QUESTION… Are you matter? Is air matter?
If you are matter…are you made of atoms? Is everything made of atoms?
Can you see atoms? Are atoms bigger or smaller than cells?
What is an atom made of? Mostly empty space!!!
AREAS OF AN ATOM INSIDE Nucleus made of protons and neutrons. All the weight of an atom is HERE!
Outside of an atom… Different ENERGY LEVELS containing… ELECTRONS They have NO weight even when there are 400 of them.
The 3 parts of an atom are… Proton, neutron, and electron Each atomic particle (part of an atom) has a size and a charge.
Protons = 1amupositive + Electrons = 0 amunegative -- Neutrons = 1amuneutral (both positive and negative ) = 0
ATOMIC RULES! #PROTONS = # ELECTRONS (positives = negatives) #PROTONS = ATOMIC NUMBER (on the periodic table) #PROTONS + #NEUTRONS = ATOMIC MASS
Difference in Atoms and Molecules • Atom is a single unit—1---Mg • Molecule is 2 or more atoms chemically combined. They are given in a formula (H2O)
Element vs. Compound • Element is on the periodic table. It has 1 capital letter • Compound is 2 or more elements combined chemically. Will be visible in a formula (H2O)
Compound vs. Mixture • Both have 2 or more atoms… • Compound is chemically combined and mixture is physically combined. There is NO formula for a mixture.
How do you find the # of atoms in a formula? • Look at each element. • Look for a number to the right of the element. • Add them together If there are NO numbers then it is 1. Add 1
How to find the # of elements in a formula? • Count the capital letters. • Each element you should have memorized from our list on the periodic table.
Periodic Table • The periodic table is an organizational tool to show relationships between elements.
Set up • The rows are called—periods PR • The columns are called—groups GC
Relationships of periods • The atomic numbers increase by 1 moving left to right. This is the number of protons THUS the number of electrons
Another relationship • The atomic mass increases from left to right but not by a specific amount because it is the number of protons + the number of neutrons
Relationship of Groups • The groups have the same number of electrons in the outer shell. • This gives them similar chemical properties because it is the electrons in the outer shell that allow bonding.