WELCOME to
WEEK 9
Our Classroom Rules...
Properties of
Materials
Chapter 2
(Chemistry)
Agenda:
discuss periodic table of elements
explain the trends in groups within
Periodic Table
enumerate reasons why elements
react to form compounds
Warm Up Activity:
Assess Prior Knowledge
˝
S level
˝
Identify the name of each symbol
S level
Na ⇒ Sodium
K⇒
Potassium
Mg ⇒ Magnesium
Li ⇒
Lithium
Sr ⇒
Strontium
Ra ⇒ Radium
Be ⇒ Beryllium
H⇒
Hydrogen
Fr ⇒
Francium
Ba ⇒ Barium
P level
˝
Identify the name of each symbol
P level
B⇒
Boron
As ⇒ Arsenic
In ⇒
Indium
Br ⇒
Bromine
Xe ⇒ Xenon
Sn ⇒ Tin
Sb ⇒ Antimony
At ⇒ Astatine
Rn ⇒ Radon
Ne ⇒ Neon
D level
˝
Identify the name of each symbol
D level
Zn ⇒ Zinc
V⇒
Vanadium
Cd ⇒ Cadmium
Au ⇒ Gold
Ag ⇒ Silver
Pt ⇒
Platinum
W⇒
Tungsten
Ti ⇒
Titanium
Mo ⇒ Molybdenum
Co ⇒ Cobalt
Atomic
Structur
e
˝
Periodic
Table
Parts
˝
˝
⇒ atoms of elements increase in mass as you progress from left to right
(starting with hydrogen) and downwards
˝
⇒ each atomic number tells how many
protons it contains and it increases
⇒ mass number tells how many protons and neutrons each atom in the
element has in total
⇒ Protons has positive charge (+) ; electrons has negative charge (-) ;
neutrons have no charge
Lithium (metal)
atomic number = 3
mass number = 7
number of protons = 3
number of electrons = ?
number of neutrons = ?
˝
Sodium (soft metal)
atomic number = 11
mass number = ?
number of protons = 11
number of electrons = ?
number of neutrons = ?
˝
˝
⇒ the higher the mass number, the more
mass the atom has
⇒ carbon has 12x more mass than hydrogen
˝
Element
measuring
mass
Iron
1 cm3
7.87g/cm3
Sodium
1 cm3
0.97g/cm3
What is atoms?
⇒ smallest particle in a matter
3 particles of atom:
⇒ protons; positive charged
particles
⇒ neutrons; neutral charge
⇒ electrons; negative charge
particles
Electrostatic attraction
⇒ positive and negative charges
JJ Thompson
⇒ 1890s, discovered electron
Ernest Rutherford
⇒ student of Thompson
⇒ from New Zealand
⇒ discovered protons1909 and
nucleus 1911
JJ Thompson
⇒ 1890s, discovered electron
Ernest Rutherford
⇒ student of Thompson
⇒ from New Zealand
⇒ discovered protons 1909 and
nucleus 1911
James Chadwick
⇒ discovered
neutrons in 1932
JJ Thompson and Ernest Rutherford
⇒ developed the model
˝
Niels Bohr
⇒ developed Rutherford’s model of the
atom further
⇒ he has the idea and evidence that the
electrons move in different electron shells
(also called as energy levels) around the
nucleus
⇒ his idea changed the structure of atom
Electronic structure
⇒ electron are arranged in electron shells
Electrostatic forces
⇒ forces that held each other in place
Do the worksheets:
In your notebook:
Draw the atomic structure of the following:
a. Na
b. Li
c. Mg
d. O
e. Neon
˝
Agenda:
discuss periodic table of elements
˝
The things to know: page 54 the table
⇒ Groups
⇒ Periods
⇒ boiling point decreasing as you go down the group
⇒ melting point decreasing as you go down the group
⇒ as atomic number increases as you go down the group
⇒ atomic mass increases as you go down the group
Notebook:
Write the atomic number, atomic mass, electron, proton, neutrons, draw the
atomic structure and tell how many electron on each shell:
Lithium
Sodium
Potassium
Group 1: The Alkali Metals
⇒ first group
⇒ very reactive chemical species, ready to lose 1 valence electron to form ionic
compounds with non - metals
Group 7: The Halogens
⇒ fluorine and chlorine are gases at room temperature
⇒ bromine is liquid
⇒ the most reactive is fluorine, then chlorine; bromine is the least reactive of the
three
⇒ they are reactive non-metallic elements that form strongly acidic compounds
with hydrogen from which simple salts can be made
Group 8: The Noble Gas
⇒ unreactive and do not form compounds
⇒ noble gases
⇒ completed the electron “8” on the outer shell
Agenda:
explain the trends in groups within
Periodic Table
2.3 WHY ELEMENTS REACT TO FORM COMPOUNDS
The shell with the
highest energy level is
the one on the outside
of the atom called
outermost electron
shell.
⇒ stable group with 8
electrons on the
outermost shell
Other groups do not have full outer shells
of electrons so they can react to form
compounds called chemical bonds.
Two ways to bond:
⇒ atoms can lose or gain electrons
⇒ atoms can share electrons
Compound:
1. H2O
2. NaCl
3. CO2
4. SO2
˝
Losing Electrons
⇒ Sodium reacts with other elements by
losing an electron
⇒ when this happens the sodium atom forms
an ion
⇒ the nest shell becomes the outermost shell
⇒ symbol will be Na+
Gaining Electrons
⇒ the outermost shell is almost full, Group 7
⇒ it will become stable
⇒ symbol Cl⇒ formed ionic bond
˝
Na+
⇒ cation (positively charged ions)
Cl⇒ anion (negatively charged ions)
Ionic Bond
⇒ an attraction between the positively
charged ion and the negatively charged ion.
˝
Atom and Ion
⇒ when the sodium loses one electron and
becomes a sodium ion
⇒ when the chlorine atom gains one electron
and becomes a chlorine ion
Naming:
lithium + chlorine ⇒ lithium chloride
lithium + fluorine ⇒ lithium fluoride
potassium + chlorine ⇒ potassium chloride
potassium + fluorine ⇒ potassium fluoride
˝
Fluorine and Chlorine
Fluorine gains an electron in the outermost
electron shell more easily than chlorine. The
electrons are held in their electron shells by
electrostatic forces between the positive
charge on the protons and the negative
charge on the electrons.
The electron in the outermost shell of fluorine
is closest to the protons so an additional
electron is attracted by the electrostatic
forces more readily than in chlorine
˝
Do page 65
numbers 1 - 6
Ionic Compounds
⇒ are those that are made from ions
⇒ formed when metal reacts with a non metal
See page 65
˝
˝
Sharing electrons
⇒ when non - metals form compounds with
non - metals
˝
˝
Agenda:
enumerate reasons why elements
react to form compounds
Worksheet/
Notebook Activity:
Worksheet Activity
Group Work
2 mins timer
In case of any doubts, send me an email on:
arlene.castillo@ro.maarifschools.org