Periodic Table and Elements

Elements Elements: A substance that cannot be broken down into a simpler substance by chemical means… Building block of all matter NOT man made, comes from the Earth

Periodic Table of Elements Groups Columns Same number of electrons in the outer shell First element in each group is the family name Ex: Group 15 (XV) is the nitrogen family Periods Rows Same number of atomic orbitals Each element in a column and row has characteristics that place it in that column and row

Periodic Table of Elements Element Name Symbol Letters that represent an element Atomic Number Atomic weight Name Atomic Weight (mass) Iron 26 Fe 55.845

The Atom Elements are made of atoms An atom is the smallest part an element can be broken down into and still keep the characteristics of that element. All atoms of an element are the same… BUT, atoms of different elements are NOT the same

The Atom The atom had three main parts Proton Neutron Positive (+), found inside the nucleus, has weight Same number as the atomic number Neutron Neutral, found inside the nucleus, has weight The number of neutrons is found by subtracting the atomic # from the atomic weight (atomic weight – atomic #)

The Atom Atomic Weight Atomic Number Electron Negative (-), found outside the nucleus on rings or orbits, spinning around the nucleus, does not have weight. Same number as the atomic number Atomic Weight # of protons + # of Neutrons Atomic Number Represents the number of protons and/or electrons in an atom

The Atom Orbital Also called a shell Outside the nucleus where electrons are found racing around

The Atom - - - - - - - - - - Electron Configuration Rule: 2-8-18-32-32-18-2 Neon: 10 protons 10 neutrons 10 electrons - - - - P: 10 N: 10 - - - - - -

Molecules/Compounds A molecule: A compound: is a stable, electrically neutral arrangement of atoms. Has 2 or more atoms held together by bonds. A compound: is a molecule with 2 or more different elements. All compounds are molecules, but not all molecules are compounds.

Molecules/Compounds Is water, H2O, a molecule or a compound? It’s both. Since water is a compound, it has 2 elements, it is automatically a molecule. How many atoms are held together in a water molecule, H2O? 3 atoms How many elements are in a water molecule, H2O? 2 elements