The Structure of an Atom

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The Structure of an Atom

• The Periodic Table

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The Atom
I. Atom- The building blocks of matter.
A. Atoms have three parts
1. Protons (Positive Charge) 2. Neutrons
(Neutral Charge) 3. Electrons (Negative Charge)
B. Protons and Neutrons are in the center of the
atom. This is called the nucleus.
C. Protons and Neutrons determine a substances
identity, and an electron determines its
reactivity.
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Periodic Table of Elements
I. The Periodic Table of Elements is the
collection of all known substances in the world.
A. Element- a substance that can not be broken
down into a simpler substance.
B. The elements on the periodic table are
arranged according to their proton, neutron,
and electron make-up.
C. There are 4 characteristics of each element
that you need to understand.
1. Atomic - This defines what the element is
or how many protons the element has.
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18 8A
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Atoms of different elements have different
atomic numbers.
Since elements are electrically neutral, the
of protons equals the of electrons.
2. Atomic Symbol This is the symbol for the
element. Could be English or Latin letters.
Why English or Latin letters?
3. Atomic Mass Average Mass of the element
or the total number of neutrons and protons in
an element.
The mass the atomic the number
of neutrons the element has.
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All atoms of a given element have the same
number of protons electrons.
Atoms of the same element can have different
numbers of neutrons. These are called isotopes.
Isotopes have the same atomic number, but a
different mass number.
4. Electron Configuration Often Called
groups.
Electron Configuration tells you where an
elements electrons are.
This determines what an element will react
with.
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Every atom goal is to have its outer energy
level (Shell) filled with electrons. If it is
filled this element is said to be stable (not
likely to react).
Group 18 (8A) are stable.
AS. of Electrons E.C.
He 2 1s2
Li 3 1s22s1
Be 4 1s22s2
O 8 1s22s22p4
Cl 17 1s22s22p63s23p5
K 19 1s22s22p63s23p64s1
Add two electrons to each s sublevel, 6 to each p
sublevel, 10 to each d sublevel, and 14 to each f
sublevel.
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Reading Information on Periodic Table
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Electron Configuration Atomic Number Symbol
Name
6 C Carbon 12.011
Memorize Atomic of protons of protons
of electrons Atomic mass of protons of
neutrons Electron Configuration of electrons
in outer most energy level (shell).
Average Atomic Mass
Why is the mass of carbon a decimal?
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Practice
1 1A
What is the atomic number of Li? How may
electrons are in Li? What is the mass number? How
many neutrons are in Li? How many electrons are
in Lis outer shell? What will Li react with
easily?
3 Li Lithium 6
Look at the periodic table in your notes What is
the name of an element that has 47 protons?
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With your partner

• Choose an element from the periodic table.
• Create a practice set of questions similar to the
  questions on slide 8 of your notes.
• Have your partner complete the questions.
• Turn in both question sets when finished.

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PARTS OF THE PERIODIC TABLE

• Period horizontal row
• Group vertical columns they are numbered 1
  18
• Family specific name describing one or more
  groups ex Column 18 is the noble gases
• Elements in the same group have the same number
  of valence electrons (electrons in their outer
  shell)

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CLASSES OF ELEMENTS

• Metals left and center part of periodic table
• Conduct heat and electricity
• Have Luster
• Malleable
• Ductile
• All are solid at
• room temperature
• (except mercury)

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CLASSES OF ELEMENTS Cont.

• Nonmetals right side of the periodic table
• Very abundant in nature
• Poor conductors of electricity and heat, brittle,
  many are gases
• Hydrogen is the only exception

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CLASSES OF ELEMENTS Cont.

• Metalloids some properties of metals and some
  properties of nonmetals
• They are found along the border between metals
  and nonmetals
• They are semiconductors

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CLASSES OF ELEMENTS Groups Activity

• You will be assigned one of the following groups
• Alkali Metals, Alkaline Earth Metals, Transition
  Metals, Boron Family, Carbon Family, Notrogen
  Family, Oxygen Family, The Halogens, The Noble
  Gases
• Create a poster that has at least 5 facts about
  the family or group assigned
• At the completion of the activity all students
  will vote for one poster in each group
• The winners will be hung outside in the hall