Chemistry 2 elements metals non metals periodic table In this Lesson:
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Elements
Metals, non-metals, metalloids
Periodic table
Trends, groups, periods
Electronic configuration
• Tom Lehrer’s “The Elements” animated 1:25
The Periodic Table
• Mendeleev and the periodic table. (5mins)
Basic version:
Periods
Even though they skip some
squares in between, all of the rows
read left to right. When you look at
the periodic table, each row is called
a period (Get it? Like PERIODic
table.). All of the elements in a
period have the same number
of shells
Example
• For example, every element in the top row (the first period) has
one shell for its electrons.
• All of the elements in the second row (the second period) have
two orbitals for their electrons. As you move down the table,
• At this time, there is a maximum of seven electron orbitals.
Electrons within a shell
Take a look at the picture. Each of those
coloured balls is an electron.
In an atom, the electrons spin around the
centre, also called the nucleus. The
electrons like to be in separate shells. The
process of separating the electrons into
shells is called electronic configuration.
Groups
The periodic table also has a special
name for its vertical columns. Each
column is called a group.
The elements in each group have the
same number of electrons in the
outer shell.
Groups
• Every element in the first column (group one) has one electron in its
outer shell. Every element in the second column (group two) has two
electrons in the outer shell.
• As you keep counting the columns, you'll know how many electrons
are in the outer shell.
• For example, nitrogen (N) has the atomic number seven. The atomic
number tells you there are seven electrons in a neutral atom of
nitrogen. How many electrons are in its outer orbital?
Questions for you.
1. Mass number = Mass of protons+mass of neutrons
Atomic number - # protons
2. How do you calculate the number of neutrons in an element?
3. What is an Isotope?Isotopes have the same number of protons but different # neutrons
Ions have less/more electrons
4. What does it mean to be an Ion?
5. What is a group on the periodic table?Group refers to # electrons in outer shell.
Period refers to # of shells
6. What is the period on the periodic table?
7. How many electrons in the first shell? 2
8
8. How many electrons in the second shell?
8
9. How many electrons in the third shell?
Metals vs non-metals / metalloids
Metals vs non-metals / metalloids
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More serious video on the differences (7mins)
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