EASY
9th CBSE
IMPORTANT
Earn 100

In neutral atoms, number of electrons are equal to number of .

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Important Questions on Structure of the Atom

EASY
9th CBSE
IMPORTANT
Together with Science Class 9>Chapter 4 - Structure of the Atom>ASSESS YOURSELF>Q 25
α-Particles are positively charged.
EASY
9th CBSE
IMPORTANT
Together with Science Class 9>Chapter 4 - Structure of the Atom>ASSESS YOURSELF>Q 26
Most part of the atom is hollow.
HARD
9th CBSE
IMPORTANT
Together with Science Class 9>Chapter 4 - Structure of the Atom>ASSESS YOURSELF>Q 27
Read the statements carefully and choose the correct alternative from the following: 
Assertion: Na, K, Ca, Mg are metals because they can lose electrons to form positive ions (cations). 
Reason: F, Cl, N, P are non-metals because they can gain electrons to form anions.
HARD
9th CBSE
IMPORTANT
Together with Science Class 9>Chapter 4 - Structure of the Atom>ASSESS YOURSELF>Q 29

What is the similarity in the electronic structure of the following set of atoms?

(a) Lithium 
(b) Sodium 
(b) Potassium 

HARD
9th CBSE
IMPORTANT
Together with Science Class 9>Chapter 4 - Structure of the Atom>ASSESS YOURSELF>Q 30

(a) Lithium 
(b) Sodium 
(b) Potassium 
Which of the above elements is most reactive and why? 

MEDIUM
9th CBSE
IMPORTANT
Together with Science Class 9>Chapter 4 - Structure of the Atom>ASSESS YOURSELF>Q 31
Find the electron distribution for the element that has atomic number 17 and write its valency.
MEDIUM
9th CBSE
IMPORTANT
Together with Science Class 9>Chapter 4 - Structure of the Atom>ASSESS YOURSELF>Q 32
The number of electrons in the outermost shell of an element is 5. What is its valency and why?
HARD
9th CBSE
IMPORTANT
Together with Science Class 9>Chapter 4 - Structure of the Atom>ASSESS YOURSELF>Q 33
Atomic number of aluminium is 13 and mass number is 27. Calculate the number of electrons, protons and neutrons in its atom. Represent the ion of this element.