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9th CBSE
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The ion of an element has 3 positive charges. Mass number of the atom is 27 and the number of neutrons is 14. What is the number of electrons in the ion?

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Important Questions on Structure Of The Atom

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9th CBSE
IMPORTANT
NCERT Exemplar Science - Class 9>Chapter 4 - Structure Of The Atom>Multiple Choice Questions>Q 10
Identify the Mg2+ ion from the figures given below where, n and p represent the number of neutrons and protons respectively
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9th CBSE
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NCERT Exemplar Science - Class 9>Chapter 4 - Structure Of The Atom>Multiple Choice Questions>Q 11
In a sample of ethyl ethanoate (CH3COOC2H5) the two oxygen atoms have the same number of electrons but different number of neutrons. Which of the following is the correct reason for it?
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9th CBSE
IMPORTANT
NCERT Exemplar Science - Class 9>Chapter 4 - Structure Of The Atom>Multiple Choice Questions>Q 12
Elements with valency 1 are
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9th CBSE
IMPORTANT
NCERT Exemplar Science - Class 9>Chapter 4 - Structure Of The Atom>Multiple Choice Questions>Q 13
The first model of an atom was given by
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9th CBSE
IMPORTANT
NCERT Exemplar Science - Class 9>Chapter 4 - Structure Of The Atom>Multiple Choice Questions>Q 14
An atom with 3 protons and 4 neutrons will have a valency of
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9th CBSE
IMPORTANT
NCERT Exemplar Science - Class 9>Chapter 4 - Structure Of The Atom>Multiple Choice Questions>Q 15
The electron distribution in an aluminium atom is 
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9th CBSE
IMPORTANT
NCERT Exemplar Science - Class 9>Chapter 4 - Structure Of The Atom>Multiple Choice Questions>Q 16

Which of the following figures do not represent Bohr's model of an atom correctly?

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9th CBSE
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NCERT Exemplar Science - Class 9>Chapter 4 - Structure Of The Atom>Multiple Choice Questions>Q 17
Which of the following statement is always correct?