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प्रश्न
Dalton's atomic theory says that atoms are indivisible. Is this statement still valid ? Give reasons for your answer.
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उत्तर
Dalton’s atomic theory states that atoms are indivisible. This statement is not valid as, atoms can be further divided into electrons, protons and neutrons. This is one of the major drawbacks of Dalton’s atomic theory of matter.
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संबंधित प्रश्न
WRITE SHORT ANSWER
Define an ionic compound.
Fill in the blank:
Atoms are _____
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
Give two examples for each of ionic and covalent bond.
What does the word ‘atom’ mean?
How did Neils Bohr visualise the atom ?
An atom has 13 protons and 14 neutrons.
How many electrons would be present in this atom ?
Fill in the blank
An excess of electrons produces a ________ charge.
Why is it not possible to see an atom even with the most powerful microscope ?
What value has been given to the mass of this reference atom ?
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.
What is the contribution of the following in atomic structure?
Maharshi Kanada
Compare:
Chlorine atom and chloride ion, with respect to
Atomic structure
Electrical state
Elements X and Y have 1 and 7 electrons in their outermost shell respectively.
What will be the charge present of the molecule XY after chemical combination?
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 4.4 g of CO2 at S.T.P ______
In the nucleus of `""_20"Ca"^40`, there are ______
1 mole of Gold and Silver contain same number of atoms.
The graphite refill used is pencil is made of element called ______.
