Atomic Structures © 2011 Project Lead The Way, Inc.Magic of Electrons

Atomic Structure Elements Atoms Components of an Atom Atomic Number Periodic Table of Elements Electrons Electron Orbits

Elements The simplest form of matter

Atoms The smallest piece of an element that contains all properties of that element

Components of an Atom Nucleus The center portion of an atom containing the protons and neutrons Protons Positively charged atomic particles Neutrons Uncharged atomic particles

Atomic Number The atomic number is equal to the number of protons in the nucleus of an atom. The atomic number identifies the element. How many protons are in this nucleus?

Periodic Table of Elements Which element has 4 protons? NASA

COMPLETE ITEM NUMBER 1 ON YOUR WORKSHEET BY LABELING THE PARTS OF THE ATOM AND IDENTIFYING IT ON THE PERIODIC TABLE.

Electrons For this unit, we mainly care about electrons in atoms. Why? It is important to understand the “how and why” of the movement of electrons to understand electricity.

Electrons Negatively charged particles

Electron Orbits Atoms work to have their valence level either filled (8) or empty(0) of electrons. How many electrons are in the valence level? 1 Copper has a loose hold on this electron, so it can easily be moved valence electrons -The outermost ring of electrons in an atom. Used to determine whether an element is an insulator, conductor or semiconductor.

Electron Orbits Atoms like to have their valence level either filled (8) or empty(0) of electrons. How many electrons are in the valence level? 6 Sulfur has space to gain two electrons in its valence level.

What does all this have to do with Electricity? The number of valence electrons in an atom will determine if an element will allow electricity to flow. The ability of an atom to draw electrons to itself (away from its neighbors) is called Electronegativity.

COMPLETE ITEMS 2 & 3 ON YOUR WORKSHEET.

Conductors and Insulators ConductorsInsulators Electrons flow easily between atoms 1-3 valence electrons in outer orbit Low Electronegativity Good Conductors: Silver, Copper, Gold, Aluminum... Electron flow is difficult between atoms 5-8 valence electrons in outer orbit High Electronegativity Examples: Mica, Glass, Rubber, Plastic...

Conductors and Insulators Identify conductors and insulators Conductors Insulators

Metals, Non-Metals, & Metalloids

Combination of metal and non-metal properties Conduct heat & electricity better than insulators, but not as good as metals Solids Semi-conductors Poor Conductors Good Insulators Dull Luster Brittle Low Density Melt at lower temps High Electronegativity Good Conductors Poor Insulators Shiny Malleable High Density Low Electronegativity

Semiconductors Include Carbon, Germanium, and Silicon Contain 4 valence electrons Neither a good insulator, nor a good conductor, but can be made a better conductor through doping. Needed for transistors and microchips Silicon is most often used in electronic applications Silicon is an insulator at room temperature but becomes a conductor when heated

Electron Flow in Conductors An atom will lose a valence electron when “pushed” by an electron from another atom.

Electron Flow Electricity is created as electrons collide and transfer from atom to atom. Play Animation

Image Resources Microsoft, Inc. (2008). Clip Art. Retrieved September 10, 2008, from National Aeronautics and Space Administration (NASA). (n.d.). Genesis: Search for origins. Retrieved September 10, 2008, from html html