THE PRESENTATION IS ABOUT THE PERIODIC TABLE, PROPERTIES OF METALS AND NON-METALS, METALLOIDS AND TRENDS OF METALS AND NON-METALS IN THE PERIODIC TABLE.
2. ABOUT MYSELF
MY NAME IS BOITHATELO SEHLAKO, A YEAR 3 STUDENT UNDWER THE
PROGRAM DIPLOMA IN PRIMARY EDUCATION AT LESOTHO COLLEGE OF
EDUCATION THABA-TSEKA CAMPUS.
3. Contents
1. Definition of the periodic table.
2. How the periodic table is made.
3. Groups and periods of the periodic table.
4. Classification of elements in the periodic table.
5. Trends in the periodic table.
4. Definition of the periodic table.
The periodic table is a method of classifying elements and predicting their
properties . These elements are listed from left to right and top to bottom
according to a property called atomic number.
It can also be defined as a chart that places all the elements in rows and
column.
5. How the periodic table is made
The periodic table is made up of rows called periods and columns called
groups. Each element is given a unique symbol, usually obtained from its
name, and is listed in order of increasing atomic number.
The atomic number is the number of protons in an atom of an element
which determines its chemical property.
Each element’s square on the periodic table include its atomic mass/
mass number which is the total mass of an atom, its name, its symbol and
atomic number.
6. Groups in the periodic table
These are the columns in a periodic table. An element is placed in a certain
group because of its valence electron, which is the number of electrons in the
outermost shell corresponds to the number of the group.
The group range from group I to group VIII.
Examples
Elements Electronic configuration groups
Sodium 2,8,1 I
Sulphur 2,8,6 VI
Magnesium 2,8,2 II
7. Periods in the periodic table
Periods are the horizontal rows of the periodic table. Elements are placed in a
period depending on the number of shells.
Examples
Elements electronic configuration period
Lithium 2,1 2
Titanium 2,8,8,4 4
Caesium 2,8,18,8,8,1 6
8. Metals in the periodic table
Metals are elements towards the left of the periodic table
Examples. Sodium, Potassium, Magnesium, Calcium.
Physical properties.
They can be hammered into thin sheets.
They can be drawn into wires.
They are good conductor of heat and electricity
Chemical properties.
They react with oxygen and form metallic oxides which are basic in nature.
They react with water and form metal hydroxide and hydrogen gas.
9. Non-metals in the periodic table
Non-metals are elements towards the extreme side of the periodic table.
Examples. Carbon, Sulfur, Nitrogen and Selenium.
Physical properties of non metals.
They are brittle as they break down into pieces on hammering.
They can not be drawn into wires because they are not ductile.
They are soft, which means they can be cut by knife easily.
Chemical properties of non-metals.
They react with oxygen and form nonmetallic oxides which are acidic in
nature.
10. Metalloids
Metalloids are elements that have properties of both metals and non-metals.
Examples
Boron
Silicon
Polonium
Properties of metalloids
They are solids
They are brittle
They are semiconductors.
11. Trends in the periodic table
Group I trends.
o They become more reactive down the group, meaning francium is the
most reactive element.
o Their fixed points decrease down the group. Lithium has the highest fixed
points in the group.
o Their softness increases down the group. Francium is the softest.
o Their density increases down the group.
Group VII trends
o Members become reactive up the group. Fluorine is the most reactive
member.
12. Trends in the periodic table
Trends in group VII
o The members become darker in colour down the group.
o They change from gaseous state to solid state down the group.
o Their densities and fixed points become high down the group.
13. CONCLUSION
The periodic table provides a systematic organization of elements, including
metals and non-metals. Understanding their properties is crucial for studying
and predicting the behavior of various substances in chemistry. It is important
to note that there are some elements that display properties of metals and
non-metals and they are called metalloids or semimetals and are located
along the diagonal stair-step line on the periodic table.
