Atoms and Ions- structure, tips to remember, grade 7 children

1. Atoms and Ions
TSRS M/Ena Gaur/2016-17
The Shri Ram School
Moulsari Campus

2. Atoms are electrically neutral!
It means, in an atom-
Number of Protons (+) = number of electrons (-)
Total Positive charge = total negative charge
TSRS M/Ena Gaur/2016-17
TIP to remember charge
on particles:
P for Protons,
P for Positive/Plus charge

3. Atoms become Ions..
 In a reaction, when atoms combine, they lose
their neutral nature and become positive or
negative to become more stable.
 When an atom has more of electrons, it will have
more – charge. This means less protons or +
charge.
OR
 When an atom has more of protons, it will have
more + charge resulting in less number of
electrons or – charge.
This imbalance results in a
charged atom called ION.
Less protons
(+ charge )
More electrons
(- charge )
TSRS M/Ena Gaur/2016-17

4. TSRS M/Ena Gaur/2016-17

5. CATIONS
 If an atom LOSES 1 electron, it means:
o The atom has 1 proton more than the electrons, resulting
in more + charge.
o Thus the atom is now positively charged and is called a
CATION.
TSRS M/Ena Gaur/2016-17

6. ANIONS
 If an atom GAINS 1 electron, it means:
o The atom has 1 electron more than the protons, resulting
in more - charge.
o Thus the atom is now negatively charged and is called an
ANION.
TSRS M/Ena Gaur/2016-17

7. TIP to remember Cations and Anions!

TSRS M/Ena Gaur/2016-17

8. Remember…
 An excess of electrons gives a negative (-)
charge making the atom an ANION.
 An excess of protons gives a positive (+)
charge making the atom a CATION.
TSRS M/Ena Gaur/2016-17

9. For example….
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10. Revise and practice Exercise 2 from your
textbook (Page 7) and complete the
table to test your learning.
TSRS M/Ena Gaur/2016-17