Download 1. discuss the contributions of early scie

LESSON PLAN 3
I. OBJECTIVES
At the end of the lesson, the students are expected to:
1. discuss the contributions of early scientists in the development of the periodic table of elements;
2. use the periodic table to locate members of given period or group and;
3. explain the difference in properties of the elements as arranged in the periodic table.
II. LEARNING TASK
A. Subject Matter
“The Periodic Table”
B. Materials
Historical review of scientist on PowerPoint; special on a non-scientist Mr. Kanzius,
who discovered a new cancer treatment.
Powerpoint Presentation
C. Teaching Strategy
Lesson Discussion
Teacher-Demonstration
D. Concepts
Periodic Table - a chart that groups the elements in increasing atomic number
Atomic number - refers to how many protons an atom of that element has
All elements have their own unique symbol. It can consist of a single capital letter, or a
capital letter and one or two lower case letters.
Symbols of elements are either the first letter or a combination of the first and any letter of
the name of the element in Latin or English.
The following are used as basis for naming the elements: discoverer’s name, place of
discovery, or its Latin or Greek name.
Valence electrons - are the electrons in the outer energy level of an atom
The elements of the periodic table can be divided into three main categories: Metals, Non –
metals and Metalloids.
Metals are good conductors of heat and electricity. Metals are shiny. Metals are ductile (can
be stretched into thin wires). Metals are malleable (can be pounded into thin sheets).
Non-metals are poor conductors of heat and electricity. Non-metals are not ductile or
malleable. Solid non-metals are brittle and break easily. They are dull. Many nonmetals are gases.
Metalloids (metal-like) have properties of both metals and non-metals. They are solids that
can be shiny or dull. They conduct heat and electricity better than non-metals but not as well as
metals. They are ductile and malleable.
Vertical Columns of elements are called groups or families. Elements in each family have
similar but not identical properties.
Horizontal rows of elements are called periods. The elements in a period are not alike in
properties.
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The hydrogen square sits atop Family AI, but it is not a member of that family. Hydrogen is
in a class of its own.
The alkali family is found in the first column of the periodic table. Atoms of the alkali metals have a
single electron in their outermost level, in other words, 1 valence electron.
The Alkaline Earth Metals have two valence electrons. Alkaline earth metals include magnesium and
calcium, among others.
Transition Elements include those elements in the B families. These are the metals you are probably
most familiar: copper, tin, zinc, iron, nickel, gold, and silver. They are good conductors of heat and
electricity.
The Boron Family is named after the first element in the family. Atoms in this family have 3 valence
electrons. This family includes a metalloid (boron), and the rest are metals. This family includes the most
abundant metal in the earth’s crust (aluminum).
Carbon Family has 4 valence electrons. The element carbon is called the “basis of life.” There is an
entire branch of chemistry devoted to carbon compounds called organic chemistry.
The nitrogen family is named after the element that makes up 78% of our atmosphere. Atoms in the
nitrogen family have 5 valence electrons. They tend to share electrons when they bond. Other elements in
this family are phosphorus, arsenic, antimony, and bismuth.
Oxygen Family has 6 valence electrons. Most elements in this family share electrons when forming
compounds. Oxygen is the most abundant element in the earth’s crust. It is extremely active and combines
with almost all elements.
Halogen Family is fluorine, chlorine, bromine, iodine, and astatine. Halogens have 7 valence
electrons, which explain why they are the most active non-metals. They are never found free in nature.
Halogen atoms only need to gain 1 electron to fill their outermost energy level.
Noble Gases are colorless gases that are extremely un-reactive. One important property of the noble
gases is their inactivity. They are inactive because their outermost energy level is full.
The thirty rare earth elements are composed of the lanthanide and actinide series. One element of
the lanthanide series and most of the elements in the actinide series are called trans-uranium, which
means synthetic or man-made.
In 1869, Dmitri Ivanovitch Mendeléev created the first accepted version of the periodic table. He
grouped elements according to their atomic mass, and as he did, he found that the families had similar
chemical properties.
Blank spaces were left open to add the new elements he predicted would occur.
E. Process Skills
Writing chemical symbols for elements
Naming elements
Explaining how the elements were given their present symbols
F. Value Focus
The students appreciate the work of early chemists in developing a system of writing symbols.
The students recognize the importance of these symbols to elements as part of a formula of
compounds.
G. References
Padolina, Ma. Cristina D. and Antero, Echel S. (2010). “The Periodic Table”, Science and
Technology,
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Conceptual and Functional Chemistry. Quezon City: Vibal Publishing House, Inc., pp. 68-77.
Brown, Theodore E. and Lemay, Eugene H. (2009). “Atoms, Molecules and Ions Chemistry –
The Central Science 11th Edition. Pearson Education, Inc., publishing as Prentice Hall, South
Asia PTE LTD., pp. 36-54.
III. LESSON PROPER
A. Review
B. Motivation
Start the lesson by asking them the meaning of some symbols like TY (thank you) and ASAP (as soon as
possible). Let them share what they know by asking them the meaning of abbreviations and acronyms. ( Write
symbols on flashcards.) Use this as a game to present the lesson.
C. Presentation
 Mendeleev produced the first successful periodic table. He arranged the elements in the order of
increasing atomic weight.
 Moseley arranged the elements in order of increasing atomic number. He summarized his discoveries by
stating the modern periodic law.
 Modern Periodic law: the properties of the elements are periodic functions of their atomic numbers.
 The modern periodic table has 118 elements arranged into periods and groups.
 Periodic table is arranged according chemical behaviors of the elements.
 Elements are grouped into groups/families and periods and collectively group into representative,
transition and inner transition.
 Elements are classified into metals, nonmetals and metalloids.
D. Recapitulation/Closure
The teacher will summarize the lesson. Refer to the Concepts for recapitulation/closure.
IV. EVALUATION
Nawamintharachinuthit Triamudomsuksapattanakarn School
Basic Chemistry (M4/10)
The Periodic Table
Name:
Score:
The Periodic Table
Direction: Choose the correct answer. Write the letter that corresponds to your answer.
1. An element has 56 protons, 56 electrons, and 58 neutrons. Its valence electron is ___________.
a. 2
c. 4
b. 3
d. 5
2. Elements with seven valence electrons are called __________.
a.
alkali metals
c.
noble gases
b.
halogens
d.
alkaline earth metals
3. All the elements below are good conductor of heat and electricity, malleable and ductile except _____
a.
Al
c.
Cu
b.
C
d.
Sn
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4. In which group does chlorine wit atomic number 17 belong?
a.
3
c.
16
b.
4
d.
17
5. Which of the following does not belong to group 1?
a.
Li
c.
K
b.
Kr
d.
Na
6. Which of the following is a noble gas?
a.
Ca
c.
Ne
b.
Mg
d.
P
7. Which of the following has the smallest atom?
a.
Ba
c.
Rb
b.
Cs
d.
Sr
8. When you move from left to right across a period, the atomic radius _____________
a.
decreases
c.
remains the same
b.
increases
d.
increases then decreases
9. All three atoms have seven electrons in the outermost energy level except ________
a.
c.
35Br
9F
b.
Cl
d.
17
7N
10. Elements on the left side of the periodic table are _____________
a.
Halogens
c.
Metalloids
b.
Inert gases
d.
Metals
Test II:
A. Use the periodic table to identify each of the following sets of elements as part of a group or a
period of elements. If the set does not represent a group or a period, write None.
1.
2.
C, Si, Ge
Li, Be, B
3.
4.
Answer:
1.
2.
P, As, Sb
O, S, Se
5.
3.
4.
Ag, Cd, Sn
5.
B. Give the symbol and name of the element that fits each of the following period and group
combinations.
1. Period 6, group 1
2. Period 3, group 17
3. Period 4, group 15
4. Period 5, group 12
5. Period 2, group 16
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C. List the following elements in order of increasing atomic radius.
a.
b.
Zn
Ca
c.
d.
Na
Cs
e.
f.
Mg
Al
Answer:
___________________________________________
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V. ASSIGNMENT
Complete the periodic table:
Prepared by: Mrs.Watcharee Janplang
Chemistry Teacher
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