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प्रश्न
A change in the physical state can be brought about
विकल्प
only when energy is given to the system
only when energy is taken out from the system
when energy is either given to or taken out from the system
without any energy change
उत्तर
when energy is either given to or taken out from the system
When energy is given to the system the solid state changes to liquid. When energy is taken out from a liquid it changes to solid e.g., ice changes to water and water to water vapours when heat energy is given. Water vapours or steam condense to water and water freezes to ice when energy is decreased.
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संबंधित प्रश्न
Why is it not possible to see an atom with naked eyes?
MATCH THE COLUMNAS
| 1. Jpham Dalton | a. Neutrons |
| 2. Atom | b. Model of the atom |
| 3. Chadwick | c.The atomic theory of matter |
| 4. Rutherfrod | d. Positively charged |
| 5. Protons | e. Electricity neutral |
| 6. Nuclear fusion | f. Generator of electricity |
| 7.Gamma -rays | g. High penetrating power |
| h.Energy in sun |
ANSWER IN DETAIL
Enlist the features of Bohr’s model of an atom. How did he correct the Rutherford’s model ?
Write the names of the elements present in the:-
Glucose
Fill in the blank
An ion with positive charge is called ______
Give the charge and the mass of an electron, proton and neutron present in an atom ?
Name two particles found inside the nucleus. What are they collectively called ?
What is the maximum number of electrons present in:
1. first shell
2. second shell
3. third shell and
4. fourth shell
Write electronic configuration of oxygen, fluorine, sodium, silicon, argon.
Name the particle or particles you would expect to find in :
The nucleus of an atom
Define: An Atom:
Fill in the blank
If an atom gains an electron, it is called an _______
Fill in the blank
An excess of electrons produces a ________ charge.
Fill in the blank
A deficiency of electrons produces a ________ charge.
How many times is a proton heavier than an electron?
Which of the following statement is correct about the atom of an element ?
A radical take part – unsplit in a chemical reaction and retains its identity in reactions.
With reference to the radical –
- ammonium
- bisulphate
- carbonate
state the group of atoms present in each radical.
Define the following term with an example.
Metalloid
What is the fundamental particle of an element?
