The Structure of an
Atom
&
The Periodic Table
“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.
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.
18
8A
* 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.
* 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.
* 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
1s22s22p63s23p64
K 19
s1
Add two electrons to each s sublevel, 6 to each p sublevel, 10 to each d
sublevel, and 14 to each f sublevel.
Reading Information on Periodic
Table
16 Electron
6A Configuration
6
Atomic Number
*Memorize*
C Atomic # = # of protons
Symbol
# of protons = # of electrons
Carbon
Atomic mass = # of protons + # of
12.011
Name neutrons
Electron Configuration = # of
Average Atomic Mass electrons in outer most energy
level (shell).
Why is the mass of carbon a
decimal?
Practice
1
What is the atomic number of
1A
Li?
3 How may electrons are in Li?
What is the mass number?
Li How many neutrons are in Li?
Lithium How many electrons are in Li’s
6 outer shell?
What will Li react with easily?
Look at the periodic table in your notes:
What is the name of an element that has 47 protons?
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.
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)
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)
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
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
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