Atomic Structure Questions ICSE class 9

Question:   Almost the entire mass of an atom is concentrated in the__________.

1.	proton
2.	electrons
3.	nucleus
4.	neutrons

Question:   Electron was discovered by___________.

1.	Chadwick
2.	Thomson
3.	Goldstein
4.	Bohr

Question:   An atom has a mass number of 23 and atomic number 11. The number of protons are_________.

1.	11
2.	12
3.	23
4.	44

Question:   The mass of the atom is determined by________.

1.	neutrons
2.	neutron and proton
3.	electron
4.	electron and neutron

Question:   The K, L and M shells of an atom are full. Its atomic number is_______.

1.	18
2.	20
3.	10
4.	12

Question:   Which of the air pressures is appropriate for the production of cathode rays in the discharge tube?

1.	1 cm Hg
2.	1 mm Hg
3.	0.001 cm Hg
4.	0.001 mm Hg

Question:   Cathode rays are deflected towards__________.

1.	positive electrode
2.	negative electrode
3.	both electrodes
4.	none of the electrodes

Question:   The absolute charge of an electron is___________.

1.	- 1.6 x 10-19C
2.	+ 1.6 x 10-19C
3.	1.6 x 10-19C
4.	16 x 10-19C

Question:   The proton is heavier than an electron by___________.

1.	1850 times
2.	1840 times
3.	1000 times
4.	100 times

Question:   Carbon-12 atom has_______________.

1.	6 electrons, 6 protons, 6 neutrons
2.	6 electrons, 12 protons, 6 neutrons
3.	12 electrons, 6 protons, 6 neutrons
4.	18 electrons, 6 protons and 6 neutrons

Question:   Chadwick got the Nobel Prize for the discovery of __________.

1.	protons
2.	neutrons
3.	electrons
4.	mesons

Question:   Mass number is equal to the_________.

1.	number of protons + number of electrons
2.	number of protons + number of neutrons
3.	number of neutrons + number of electrons
4.	number of electrons

Question:   The element X has 2 valence electrons. It is a____________.

1.	metal
2.	non-metal
3.	metalloid
4.	gas

Question:   The volume of the nucleus of an atom when compared to the extra nuclear part is_________.

1.	bigger
2.	smaller
3.	same size
4.	unpredictable

Question:   In Rutherford's alpha-scattering experiment, a foil of element that was used _______________.

1.	gold
2.	silver
3.	aluminum
4.	magnesium

Question:   An element has an electronic configuration of 2, 8, 7. Its valency is

1.	1
2.	7
3.	17
4.	8

Question:   The other name of is _________

1.	protium
2.	tritium
3.	deuterium
4.	proton

Question:   During a chemical reaction, atomic number_________.

1.	changes
2.	remains same
3.	changes and then is restored
4.	changes alternately

Question:   The fixed circular paths around the nucleus are called_________.

1.	orbits
2.	orbitals
3.	nucleons
4.	mesons

Air and Water Worksheet class 6

(Q.1)  Name the main component of compressed natural gas.
(Q.2)  Give one use of nitrogen gas.
(Q.3)  Name one fossil fuel used for generation of electricity.
(Q.4)  Name a gas which is present in air in very small amount.
(Q.5)  Where does nitrogen fixation occurs in plants?
(Q.6)  Which gas is required for release of energy from glucose in the bodies of living organisms during combustion of food?
(Q.7)  What are the two substances necessary for rusting of iron?
(Q.8)  Name two pollution free clean fuels.
(Q.9)  What are the main constituents of LPG?
(Q.10)  Name three important processes that cannot be performed in absence of oxygen.
(Q.11)  a. Name two green house gases. b. What effect these gases produce on our atmosphere?
(Q.12)  a. Name the components of air. b. Write four uses of air.
(Q.13)  Why do wet clothes dry up quickly in sunlight compared to shades?
(Q.14)  How do fish and aquatic plants survive in water?
(Q.15)  Which liquid is called universal solvent and why?
(Q.16)  �Define the following (i) Transpiration    ii) Cloud
(Q.17)  Which process is involved in the removal of salt from the sea water?
(Q.18)  Name the water body which contains the highest concentration of salt in it?
(Q.19)  Why is water used as coolant in the radiator of engines?

(Q.20)  In which form water is present in atmosphere?
(Q.17)  Name the only substance which occurs in three states under the temperature range of 0 �C to 100 �C.
(Q.18)  Name the phenomenon by which plants loses water from their leaves.