Atoms and the Periodic Table

Atomic Structure Based on the current Electron Cloud Model Neutron Found in the nucleus Has no charge Mass is 1 amu Nucleus Contains protons and neutrons Has an overall positive charge Contains most of atom’s mass Proton Found in the nucleus Has a positive charge Mass is 1 amu Electron Found outside of the nucleus in the electron cloud, arranged in energy levels (shells) Has a negative charge Electron Cloud is mostly empty space and determines the size of the atom.

Development of the Periodic Table Russian scientist who created a periodic table which organized elements by atomic weight (mass) and similar properties.

What is an element? Basic substance on Earth that cannot be broken down into any other substance. Represented by a symbol (capital letter or capital and lowercase letters) Example: O (oxygen) Au (gold)

What is a compound?

Element or Compound?

Element or Compound? Compound Hydrogen, Sulfur, Oxygen Element Helium Chromium, Nitrogen, Hydrogen, Oxygen Compound Magnesium, Nitrogen, Oxygen Compound Barium, Phosphorus, Oxygen Element Oxygen Compound Hydrogen, Phosphorus, Oxygen Compound Zinc, Oxygen, Hydrogen Element Carbon

Common Household Compounds CaCO3 NaHCO3 NaClO NaCl NH3 C9H8O3

Periodic Table of Elements

Groups or Families Periods 18 7 periods Elements within the same period have the same number of energy levels or electron shells. They have the same number of valance electrons and have similar properties. Groups 1 and 17 are highly reactive because they want to either give or receive 1 valance electron

Using the Periodic Table Atomic Number – tells us the number of protons and electrons Element Symbol Atomic Mass – tells us the total number of protons and neutrons Element Name

Using the Periodic Table tomic Number ass rotons tomic Number lectrons eutrons

Practice

Practice Answers

The Atoms Family Math Challenge Atoms Family Song

Understanding Chemical Formulas What is a chemical formula? Chemical formulas are a way to show which elements and how many atoms of each element are in a compound.

Chemical Formula Example

Counting Atoms be

Counting Atoms Practice 1 1 5 2 6 1 8 3 10 3 6 3 9 3 13 3

Chemical Equations A chemical equation is a written representation of the process that occurs in a chemical reaction. A chemical equation is written with the reactants on the left side of an arrow and the products of the chemical reaction on the right side of the equation.

Chemical Equations

Balancing Chemical Equations The Law of the Conservation of Mass says that every atom that “goes into” a chemical reaction must “come out of” the chemical reaction. To balance a chemical equation you must have the same number of atoms on each side. 2H2 + O2 2H2O So count the atoms for each side: H – 4 O - 2 H – 4 O - 2

Balanced or Unbalanced? Determine whether or not the equation is balanced or not. Write a “B” for Balanced and a “U” for Unbalanced B B B B U B B