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प्रश्न
How did Neils Bohr visualise the atom ?
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उत्तर
Niels Bohr explained that atom is like a solar system with an empty space with a minute central nucleus, like Sun and electrons life planets revolve around it.
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संबंधित प्रश्न
If bromine atom is available in the form of, say, two isotopes `""_35^79Br (49.7%)" and """_35^81Br (50.3%)`, calculate the average atomic mass of bromine atom.
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 |
WRITE SHORT ANSWER
What is radioactivity?
ANSWER IN DETAIL
How are isobars different from isotopes ?
Write the names of the elements present in the:-
Glucose
Fill in the blank
An ion with positive charge is called ______
Define: Chemical bond
What are the building blocks of matter ?
One nm is equal to :
The electronic configuration of an element Z is 2, 8, 8.
(a) What is the atomic number of the element?
(b) State whether element Z is a metal or a non-metal.
(c) What type of ion (if any) will be formed by an atom of element Z? Why?
(d) What is special about the outermost electron shell of the atom of this element?
(e) Give the name and symbol of element Z.
(f) Name the group of elements to which Z belongs.
How many atoms are there in exactly 12 g of carbon-12 element ? (C = 12 u)
Calculate the number of moles in 12.044 × 1025 atoms of phosphorus.
Define the following term:
Atom
Match the pairs.
| Group 'A' | Group 'B' |
| a. Proton | i. Negatively charged |
| b. Electron | ii. Neutral |
| c. Neutron | iii. Positively charged |
Elements X and Y have 1 and 7 electrons in their outermost shell respectively.
Which element will lose electron?
Select the correct answer to the statement given below:
The smallest particle of a substance – capable of independent existence and which retains the characteristics of the substance.
Project.
To have an idea of what atoms are, students can be asked to construct atoms using pipe cleaners (thin metal wires-electron shells), pompoms (balls-different colours for protons and neutrons) and beads (electrons). Students will love and enjoy putting them together and they look great hanging from the ceiling in the classroom.
The volume occupied by 1 mole of a diatomic gas at S.T.P is ______
The number of atoms present in a molecule is called its ______.
The ______ are combination of atoms of various elements or the same element.
