From the table given below to answer the following questions Element A B C D E Mass number 11 19 3 23 9 Atomic number 5 9 2 11 4 How many electrons are present in 'E'?

Atomic number of E = 4 We know that, Electrons in E = Atomic number of E Electrons in E = 4

From the table given below to answer the following questions Element A B C D E Mass number 11 19 3 23 9 Atomic number 5 9 2 11 4 Which of the above is an inert gas and why?

From table, we can say that C is an inert gas because the atomic number of C is 2 so the electronic configuration of C is ( 2 ) . This proves that, its outer shells are completely filled and cannot accept more electrons hence inactive or inert in nature.

From the table given below to answer the following questions Element A B C D E Mass number 11 19 3 23 9 Atomic number 5 9 2 11 4 Which atom will form negatively charged ion?

First we find electron configuration of each element, For, A = (2,3) B = (2,7) , C = (2) , D = (2,8,1) and E = (2,2) During reaction atoms have tendency to keep their outer shell completely filled so we can see if B gain one electron it's outer orbit L will become completely filled and form negative charge. Hence, B will form negative charged ion

From the table given below to answer the following questions Element A B C D E Mass number 11 19 3 23 9 Atomic number 5 9 2 11 4 Which Element has 12 neutrons? why?

To calculate the number of electrons we use, Neutrons = Mass Number - Atomic number Using this relation A = 11-5 = 6 neutrons B = 19 - 9 = 10 neutrons C = 3-2 = 1 neutron D = 23-11 = 12 neutrons E = 9-4 = 5 neutrons Hence D has 12 neutrons

From the table given below to answer the following questions Element A B C D E Mass number 11 19 3 23 9 Atomic number 5 9 2 11 4 Which atoms will form cation with one positive charge?

First we find electron configuration of each element, For, A = (2,3) B = (2,7) , C = (2) , D = (2,8,1) and E = (2,2) During reaction atoms have tendency to keep their outer shell completely filled, so we can see if D loses one electron it's outer orbit L will become completely filled and form single positive charge. Hence, D will form cation with single positive charge.

Composition of nuclei of two atomic species 'X' and 'Y' are given below. X Y Protons 8 8 Neutrons 8 10 Write the mass number of X and Y respectively.

Mass number of an element is the sum of proton and neutrons present in the nuclei of the atom. Mass number of X = 8 + 8 = 16 Mass number of Y = 8+10 = 18

Calculate the number of atoms in i 52 g of He

EASY

9th CBSE

IMPORTANT

Together with Science Class 9>Chapter 17 - Practice Paper 2>2; PRACTICE PAPER>Q 31

Calculate the number of atoms in

(i) 52 moles of He

EASY

9th CBSE

IMPORTANT

Together with Science Class 9>Chapter 17 - Practice Paper 2>2; PRACTICE PAPER>Q 31

State the law of conservation of mass. Illustrate the law with an example.

EASY

9th CBSE

IMPORTANT

Together with Science Class 9>Chapter 17 - Practice Paper 2>2; PRACTICE PAPER>Q 32

From the table given below to answer the following questions

Element	A	B	C	D	E
Mass number	11	19	3	23	9
Atomic number	5	9	2	11	4

How many electrons are present in 'E'?

EASY

9th CBSE

IMPORTANT

Together with Science Class 9>Chapter 17 - Practice Paper 2>2; PRACTICE PAPER>Q 32

From the table given below to answer the following questions

Element	A	B	C	D	E
Mass number	11	19	3	23	9
Atomic number	5	9	2	11	4

Which of the above is an inert gas and why?

EASY

9th CBSE

IMPORTANT

Together with Science Class 9>Chapter 17 - Practice Paper 2>2; PRACTICE PAPER>Q 32

From the table given below to answer the following questions

Element	A	B	C	D	E
Mass number	11	19	3	23	9
Atomic number	5	9	2	11	4

Which atom will form negatively charged ion?

EASY

9th CBSE

IMPORTANT

Together with Science Class 9>Chapter 17 - Practice Paper 2>2; PRACTICE PAPER>Q 32

From the table given below to answer the following questions

Element	A	B	C	D	E
Mass number	11	19	3	23	9
Atomic number	5	9	2	11	4

Which Element has 12 neutrons? why?

EASY

9th CBSE

IMPORTANT

Together with Science Class 9>Chapter 17 - Practice Paper 2>2; PRACTICE PAPER>Q 32

From the table given below to answer the following questions

Element	A	B	C	D	E
Mass number	11	19	3	23	9
Atomic number	5	9	2	11	4

Which atoms will form cation with one positive charge?

EASY

9th CBSE

IMPORTANT

Together with Science Class 9>Chapter 17 - Practice Paper 2>2; PRACTICE PAPER>Q 32

Composition of nuclei of two atomic species 'X' and 'Y' are given below.

	X	Y
Protons	8	8
Neutrons	8	10

Write the mass number of X and Y respectively.

Calculate the number of atoms in

(i) 52 g of He

Important Questions on Practice Paper 2

Learn and Prepare for any exam you want !

Calculate the number of atoms in (i) 52 g of He

Important Questions on Practice Paper 2

Learn and Prepare for any exam you want !

Calculate the number of atoms in

(i) 52 g of He