Ch. 7.1 - Part 1 - The Elements
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Transcript of Ch. 7.1 - Part 1 - The Elements
Ch. 7.1 - Part 1 -
The ElementsCHM Hon.
First, things to Remember…
• What is IONIZATION ENERGY? What is the general trend?
• What is ELECTRONEGATIVITY? What is the general trend?
• What are the REPRESENTATIVE ELEMENTS and why are they called “representative”?
Properties of s-block elements
• There are 92 naturally occurring elements in the Universe
Properties of s-block elements
• Representative elements– Group 1A – 7A– Valence electrons: # and location determine
the chemical properties• Metals: tend to lose electrons• Nonmetals: tend to gain electrons
Properties of s-block elements
• Diagonal relationships– The close relationship between elements in
neighboring groups
Properties of s-block elements
• Diagonal relationships– Some period 2 elements do not behave as
predicted by their location on the p.t.– Period 2 elements have more in common with
period 3 elements in the next group
Properties of s-block elements
• HYDROGEN– Group 1A– 1 Valence electron– Not part of any specific group
• Has properties of a metal and a nonmetal
Properties of s-block elements
• HYDROGEN– Discovered by Henry
Cavendish 1776• Flammable air
Properties of s-block elements
– HYDROGEN• Named Hydrogen by Lavoisier 1783
– “to form water” hydro + genes
Properties of s-block elements
• HYDROGEN– Universe is more than 90 % H by mass– 3 isotopes
• Protium (99.9%) H-1• Deuterium H-2
– Used in nuclear reactors - “heavy water”
• Tritium H-3
Properties of s-block elements
• HYDROGEN– Acts like both a metal and nonmetal– Nonmetal
• Gains an electron• Acquires the stable electron configuration of He
– Metal• Acts like a metal when reacting with a nonmetal • Loses its single electron becomes a H+ ion