Hello Chemistry Students: 9/21/15 ChemCatalyst: 1. What are the three particles atoms are made of? 2. Draw a atom.

The Atom: Calculating Protons, Neutron, and Electrons Chemistry/Pre-AP Chemistry Ms. Lizette Gutierrez Austin High School

What is an Atom? 0 The atom is the smallest part of an element that still retains the properties of that element. 0 First proposed by Democritus

Structure of the Atom Atoms are composed of 2 regions: 0 Nucleus 0 The center of the atom 0 Contains 99.9% mass of the atom 0 Hold protons and neutrons 0 Dense part of atom 0 Electron cloud 0 Area surrounding the nucleus 0 Contains must of the volume of the atom 0 Mostly empty space 0 Holds electrons

Subatomic Particles An atom is composed of three subatomic particles: 0 Proton (+) 0 It’s a particle located IN THE NUCLEUS of an atom 0 It has a charge of +1 0 mass of 1 amu (atomic mass units). 0 The protons determine the identity of element (Atomic Number) 0 Neutron (0) 0 It’s a particle located IN THE NUCLEUS of an atom 0 It has a charge of 0 (no charge) 0 mass of 1 amu (atomic mass units) 0 Electron (-) 0 It’s a particle located AROUND THE NUCLEUS of an atom 0 It has a charge of -1 0 mass of 0 amu (atomic mass units)

How do the subatomic particles balance each other? In an Neutral atom (assume): 0 # PROTONS = # ELECTRONS 0 A neutral atom has an overall electrical charge of Zero, because it contains the same number of protons (+) and electrons (-). 0 The neutrons have no charge; therefore they do not have to equal the number of protons or electrons Carbon Atom 6 protons (+) = +6 6 electrons (-) = -6 6 neutrons (0) = 0 ____________________ 0 (neutral) Carbon Atom 6 protons (+) = +6 6 electrons (-) = -6 6 neutrons (0) = 0 ____________________ 0 (neutral) +

Bohr Model (Simplest Atomic Structure) Energy Levels: circular areas around the nucleus where electrons travel Electrons in an atom are contained in specific energy levels (1, 2, 3, …) that are different distances from the nucleus. Energy Levels: circular areas around the nucleus where electrons travel Electrons in an atom are contained in specific energy levels (1, 2, 3, …) that are different distances from the nucleus. Electron Cloud Electron (-) Neutron (0) Nucleus Proton (+)

Models of Atoms Bohr Model

Basic Atomic Structure Foldable 0 Using this PowerPoint fill in the information for each flap on your foldable 0 Glue into your Notebook. 0 Title: “THE ATOM” 0 BE NEAT! 0 Coloring Instructions 0 PROTONS – highlight pink 0 NEUTRONS– highlight green 0 ELECTRONS – highlight orange