Elements & Compounds Notes

Raise your hand if you have ever heard of the following…………. Hydrogen Oxygen Helium Gold Silver Carbon Chlorine Strontium

Very Good! You are already familiar with different elements. How would you define an element?

Element A pure substance that cannot be separated into simpler substances Most occur naturally and some are made in a lab

Each element has a name and a chemical symbol of either 1 or 2 letters Ex: H – Hydrogen O- Oxygen Na – Sodium He- Helium There are over 100 known elements

Periodic Table of Elements Elements are grouped together on the Periodic Table based on their atoms. Each square on the table represents a different element. It shows the name, chemical symbol, atomic number, and atomic mass.

Now that you understand elements, what is a compound?

Compounds Are made of atoms of different elements that are bonded together Ex: H 2 O –Water

NaCl Sodium Chloride (Salt!)

CO 2 Carbon Dioxide

So how are elements and compounds different? Elements can’t be separated, compounds can Elements are on the periodic table, compounds are not Compounds are a combo of elements

Practice, Practice, Practice Find the following elements on the Periodic Table in your book (pg 658). Write down their name and symbol in your notes. SodiumNickel Sulfur PotassiumArgon Lithium CarbonBoronNitrogen Calcium Lead Neon

Metals, Nonmetals, Metalloids Metals Silver/ gray in color (except for Copper and Gold) Hard, solid (except for Mercury which is a liquid) Malleable- can be pounded into thin sheets Ductile- can be pulled into wires Good conductors of electricity and heat Oxidize- react to Oxygen and rust forms

Metalloids Solid Located on stair step between metals and nonmetals on periodic table. Have properties of metals and nonmetals Semi- conductors

Nonmetals Not able to conduct electricity or heat Are not malleable or ductile Many are gas and a few are solid

ElementChemical Symbol Atomic Number Metal Nonmetal Metalloid Solid, Liquid, Gas