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प्रश्न
State Dalton’s atomic theory.
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उत्तर
- Matter is made up of tiny particles called atoms
- Atoms are indivisible.
- Atom can be neither be created nor destroyed.
- Atoms of same element are identical in mass and properties
- Atoms of different elements differ in mass and properties
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संबंधित प्रश्न
TRUE \ FALSE
Cathode rays are a stream of fast moving particles that travel in random directions.
WRITE SHORT ANSWER
Define an ionic compound.
Define:- Atom
Fill in the blank
An ion with positive charge is called ______
Define: Mass number
An atom has 13 protons and 14 neutrons.
What is the atomic mass of the atom ?
A certain particle ‘X’ has 17 protons, 18 electrons and 20 neutrons.
What is the atomic numebr of X ?
Fill in the blank
A deficiency of electrons produces a ________ charge.
An atom of an element X may be written as `""_9^4"X"`
(a) What does the figure 9 indicate?
(b) What does the figure 4 indicate?
(c) What is the number of protons in atom X?
(d) What is the number of neutrons in atom X?
(e) What is the number of electrons in atom X?
(f) How many electrons are there in the outermost shell of an atom of element X?
(g) Write the symbol of ion formed by an atom of element X.
Give scientific reason.
All the mass of an atom is concentrated in the nucleus.
Select the correct answer to the statement given below:
The basic unit of matter is not capable of independent existence.
Assertion: An atom is electrically neutral.
Reason: Atoms have equal number of protons and electrons.
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.
Define the following term with an example.
Metalloid
Define the term ions or radicals.
Give the salient features of “Modern atomic theory”.
A sample of vitamic C is known to contain 2.58 ×1024 oxygen atoms. How many moles of oxygen atoms are present in the sample?
An atom of Oxygen (O) and two atoms of hydrogen (H.) combine to form a molecule of ______.
What is the fundamental particle of an element?
