Chemistry Vocabulary and Notes The Atom Chemistry Vocabulary and Notes Power points are for you to use if you want. Feel free to edit to fit your classroom.

What is an atom? An atom is the smallest particle into which an element (such as gold) can be divided and still maintain the properties of that element.

Vocabulary - 1 ELEMENT -substance that cannot be broken down into other substances by chemical/physical means ATOMIC NUMBER -number of protons in nucleus ATOMIC MASS UNIT (amu)-unit used to measure particles in atoms VALENCE ELECTRON - electrons located farthest away from nucleus CHEMICAL BOND - force that holds chemicals together Put in foldable – include picture. Spanish word Assign homework: 1. Use word in a sentence

ATOMIC STRUCTURE Atoms are made up of even smaller particles called protons, neutrons, and electrons. PROTONS (+)– positively charged particles located in the nucleus NEUTRONS (0)– electrically neutral particles located in the nucleus ELECTRONS (-)– negatively charged particles found outside the nucleus

ATOM Put model on front of foldable - matchbook

Atom Notes Nucleus-core of atom, made of proton (+), neutrons Atom neutral when protons = electrons (-) Atomic number = number of protons AMU measures particles in atom Electrons roam around nucleus in electronic cloud – are in constant motion Protons have almost 2000 times as much mass as electrons Electrons attract protons in nearby atoms Attraction forms molecules

Atom Notes - cont. Atomic Mass = number of protons + number of neutrons 1st shell = 2 2nd shell = 8 3rd shell = 18 4th shell = 32 5th ,6th,7th have various amounts, depending on type of molecule formed with max of 32, 18, and 2 respectively Most of the atom’s volume is the space where the electrons move

Valence Electrons Are the electrons that are farthest away from the nucleus Determines many properties of the atom and therefore of the element Forms chemical bonds with other atoms Can range from 1 to 8 Are represented by an electron dot diagram                                                 

Lewis Electron Dot Diagram Lewis Electron Dot Diagrams are a type of model that displays the number of valence electrons an atom has. Dots are added one at a time to the outside of the chemical symbol in a circle until they match the number of valence electrons. Lewis Electron Dot Diagram for Chlorine