Transcript Symbols of atoms with dots to represent the valence-shell

BELLRINGER
EXPLAIN IN COMPLETE
SENTENCES THE BASICS OF
CHEMICAL BONDS STRUCTURE
ELEMENT OF THE DAY
Argon
Ar
ATOMIC NUMBER 18
ATOMIC WEIGHT 39.948
Inert, noble gas
ATOMIC STRUCTURE: 18p, 18e, 20n
ELECTRONIC STRUCTURE: 2, 8, 8
WHAT ARE
Atom – the smallest unit of matter “indivisible”
Helium
atom
electron shells
a) Atomic number = number of Protons or
Electrons
b) Electrons vary in the amount of energy
they possess, and they occur at certain
energy levels or electron shells.
c) Electron shells determine how an atom
behaves when it encounters other atoms
Electrons are placed in shells
according to rules:
1) The 1st shell can hold up to two electrons,
and each shell thereafter can hold up to 8
electrons.
Octet Rule = atoms tend to gain, lose or share electrons so
as to have 8 electrons
C would like to Gain 4 electrons
N would like to Gain 3 electrons
O would like to Gain 2 electrons
Why are electrons important?
1) Elements have different electron
configurations
 different electron configurations mean
different levels of bonding
Electron Dot Structures
Symbols of atoms with dots to represent the valence-shell
electrons
1
2
13
14
15
16
17
H
18
He:

Li Be


B 


C


Na Mg


Al

N



O




 Si 
P
 S





: F  :Ne :




:Cl  :Ar :


Chemical bonds: an attempt to fill electron shells
1. Ionic bonds –
2. Covalent bonds –
3. Metallic bonds
Activities
1.
EACH GROUP WORKS ON THE element GIVEN ON THE BOARD
2.
YOU DRAW OCTET DOT STRUCTURE OF
YOUR ELEMENT IN THE WAY I DID FOR Argon ON THE BOARD
3.
AFTER YOU FINISHED, YOUR GROUP LEADER PRESENTS
THE RESULT
Group 1 - P, 2 - Si, 3 - Al, 4 - Mg, 5 - Na, 6 - Ne,
7 - Cl, 8 - O, 9 - N, 10 - C
Lesson conclusion
1.
Octet Rule = atoms tend to gain, lose or share electrons so as to have
8 electrons
2.
Electron shells determine how an atom behaves when it encounters
other atoms
3.
Electron Dot Structure - Symbols of atoms with dots to represent
the valence-shell electrons
4.
Chemical Bonds: Ionic bonds , Covalent bonds , Metallic bonds
EXIT QUIZ
1. Describe various types of chemical bonds.
2. Predict properties of chemical bond using
electronic structure of chemical bond.
3. 3. Evaluate # of electrons in outer orbital of each
bond component using atomic number and
electronic structure of components.