Atomic Weight

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Atoms Lesson - Atomic Weight - Elementary Science Lessons & Tests - My Schoolhouse - Online Learning
 

Atoms have charges.  There are two kinds of charges.  There are positive (+) charges and negative (-) charges.  Scientists have discovered that some parts of an atom have positive charges and other parts have negative charges.

PROTONS - have positive charges (+)

ELECTRONS - have negative charges (-)

NEUTRONS - have no charges.  They are neutral.

An atom has the same number of protons and electrons.  Notice on the diagram below there are 2 protons and 2 electrons.

Atom Picture

The number of neutrons and protons of an atom is called its atomic weight (mass).

Each PROTON is given a weight of one.

Each NEUTRON is given a weight of one.

Here's an example:

Name of Element

Number of Protons

Number of Neutrons

Atomic Weigh

cobalt

27

32

59

 

Practice finding the atomic weight of each of the elements listed below.  Remember the atomic weight equals the sum of the protons and neutrons.

Name of Element

Number of Protons

Number of Neutrons

Atomic Weigh
zinc 30 35
krypton 36 48
potassium 19 20
silver 47 61
lead 82 125
oxygen 8 8
hydrogen 1 0

calcium

20

20

 

Directions: Answer the questions about atomic weight.

A has a positive charge.

An  has a negative charge.

A has no charge.

The number of and protons of an atom is called its atomic weight (mass).

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 
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