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 ElectronsChemistry/Pre-AP ChemistryMs. Lizette GutierrezAustin High School

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

0First proposed by Democritus

Structure of the AtomAtoms are composed of 2 regions:

0Nucleus0 The center of the atom 0Contains 99.9% mass of the atom0Hold protons and neutrons0Dense part of atom

0Electron cloud0Area surrounding the nucleus0Contains must of the volume of

the atom0 Mostly empty space 0Holds electrons

Subatomic Particles An atom is composed of three subatomic particles:

0Proton (+)0 It’s a particle located IN THE NUCLEUS of an atom0 It has a charge of +1 0 mass of 1 amu (atomic mass units). 0 The protons determine the identity of element (Atomic

Number)0Neutron (0)

0 It’s a particle located IN THE NUCLEUS of an atom0 It has a charge of 0 (no charge)0 mass of 1 amu (atomic mass units)

0Electron (-)0 It’s a particle located AROUND THE NUCLEUS of an atom0 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 = # ELECTRONS0A 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 (+) = +66 electrons (-) = -66 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.

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 pink0 NEUTRONS– highlight green0 ELECTRONS – highlight orange