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The Periodic Table. YOU WILL WRITE WHAT IS RED INTO YOUR NOTES. Why is the Periodic Table important?. The periodic table is the most useful tool to a chemist. It allows predictions about how a substance or element will react.
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The Periodic Table YOU WILL WRITE WHAT IS RED INTO YOUR NOTES
Why is the Periodic Table important? • The periodic table is the most useful tool to a chemist. • It allows predictions about how a substance or element will react. • It organizes a lot of useful information about all the known elements.
Pre-Periodic Table Chemistry … • …was a mess!!! • No organization of elements. • Imagine going to a grocery store with no organization!! • Difficult to find information. • Chemistry didn’t make sense.
HOW HIS WORKED… Put elements in rows by increasing atomic weight. Put elements in columns by the way they reacted. SOME PROBLEMS… He left blank spaces for what he said were undiscovered elements. (Turned out he was right!) He broke the pattern of increasing atomic weight to keep similar reacting elements together. Dmitri Mendeleev:Father of the Table Mendeleev video
The Current Periodic Table • Mendeleev wasn’t too far off. • Now the elements are put in rows by increasing ATOMIC NUMBER!! • The horizontal rows are called periods and are labeled from 1 to 7. • The vertical columns are called groups are labeled from 1 to 18.
Groups…Here’s Where the Periodic Table Gets Useful!! • Elements in the same group have similar chemical and physical properties!! • (Mendeleev did that on purpose.) • Why?? • They have the same number of valence electrons; the electrons located on the outer orbital.
Valance Electrons • Looking at your Periodic Table’s columns, what element is this?
Families on the Periodic Table • Columns are grouped into families; Valence Electrons • Families have names rather than numbers. (Just like your family has a common last name.) Families
Knowledge Keeps you Alive • By understanding where the elements are located in the periodic table, you can make very experienced predictions as to how they will act with other element or compounds. Professor Hunter
Hydrogen • Hydrogen belongs to a family of its own. • Hydrogen is a explosive, reactive gas. • Hydrogen was involved in the explosion of the Hindenberg. • Hydrogen is promising as an alternative fuel source for automobiles Hindenburg Video Colour Hydrogen Brown on your P.T.
Alkali Metals (1 Valance e-) • 1st column on the periodic table (Group 1) not including hydrogen. • Very reactive metals, always combined with something else in nature (like in salt) • Ex. NaCl or KCl • Soft enough to cut with a butter knife Brainiacs Alkali Metals Video Video Colour the Alkali Family Blue
Alkaline Earth Metals (2 Valance e-) • Second column on the periodic table. (Group 2) • Reactive metals that are always combined with nonmetals in nature. • Several of these elements are important mineral nutrients (such as Mg and Ca) Video Start at 35s Colour the Alkaline Earth Family Grey
Transition Metals • Elements in groups 3-12. • We don’t need to know them at this time…
Boron Family (B) (3 Valance e-) • Elements below Boron. • Aluminum metal was once rare and expensive, not a “disposable metal.” Video Colour the Boron Family Purple
Carbon Family (C) (4 Valance e-) • Elements below CARBON. • Contains elements important to life and computers. • Carbon is the basis for an entire branch of chemistry. • Silicon and Germanium are important semiconductors. Colour the Carbon Family Red
Nitrogen Family (5 Valance e-) • Elements below Nitrogen. • Nitrogen makes up 78 % of the atmosphere. • Nitrogen and phosphorus are both important in living things. Colour the Nitrogen Family Orange
Oxygen Family (6 Valance e-) • Elements below Oxygen. • Oxygen is necessary for respiration (energy) • Many things that stink, contain sulfur (rotten eggs, garlic, skunks, etc.) Video Leave the Oxygen Family White
Halogens Group (7 Valance e-) • Elements below Fluorine. • Very reactive, volatile nonmetals. • Always found combined with other element in nature . Video Colour the Noble Family Yellow
The Noble Gases(8 Valance e-, except He with 2 valence e-) • Elements below Helium. • VERY unreactive, monatomic gases • Used in lighted “neon” signs. • Used in blimps to fix the Hindenberg problem. • Have a full valence shell. Video Colour the Noble Gas Family Green Table Song
Making Molecules Molecules are MULTI-ATOM particles. • They are the smallest particle of a substance that still keeps the characteristic properties of that substance. • It is composed of 2 or more atoms. • A compound forms when two or more elements are bonded.
How do they stay together? • Because atoms are made of electrical charges (positives and negatives); they are either attracted to each other, or repelled from one another – like magnets. • The atom’s valance electrons dictate which element it will be attracted to. Simple Bonding video 15 sec
Chemical Formulas • The elements found in chemical formulas easily show which elements are present and how many. • By either knowing an elements symbol, or having a periodic table around you can make excellent choices as to what is found in each molecule or compound. 2 Hydrogen Atoms 1 Oxygen Atoms = H2O Water Molecule
Name the following compounds: 1) NaBr ______________ 2) CaO ______________ 3) Li2S _______________ 4) MgBr2 _____________ 5) NO2 ______________ 6) SO3 _______________ 7) N2S _______________ 8) PH3 _______________ 9) BF3 _______________ 10) P2Br4 _____________ 11) CO ___________ 12) SiO2 __________ 13) SF6 ___________ 14) NH3 ___________ 15) C6H12O6 ___________ 16) Be(OH)2 ___________ Name the Elements in the Molecule
Drawing Molecules: Valence Electrons • NaCl • CaO Your turn: NaBr CaS Li2S MgBr2
Family Relationships 1a) What are the 7 Alkali Metals that will easily bond with Fluorine? Lithium, Sodium, Potassium, Rubidium, Cesium, Francium b) What other elements in the Halogen Family with bond with any of the Alkali Metals? Chlorine, Bromine, Iodine and Astatine c) Will any of the Elements in the Alkaline Earth Metals bond with any of the Halogens? Explain. Sure. Because all of the A.E.M.s have 2 valence electrons, any two of the halogens would bond with any of them.
How about Carbon? • From what you understand, how many atoms could bond with Carbon? ExplainCarbon Video