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प्रश्न
Dalton said that ______ could not be divided.
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उत्तर
Dalton said that atoms could not be divided.
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संबंधित प्रश्न
Fill in the blanks.
Isotopes are the atoms of ______ element having the ______ atomic number but ______ mass number.
The atom of an element is made up of 4 protons, 5 neutrons and 4 electrons. What is its atomic number and mass number?
Elements X, Y and Z have atomic numbers 6,9 and 12 respectively. Which one:
- Forms an anion
- Forms a cation
Match the statements in List I with the correct answer from List II.
| List I | List II |
| 1. Mass number of an atom is the number of protons and | A: Electron |
| 2. The sub-atomic particle with a negligible mass. | B: Argon |
| 3. An atom having stable electronic configuration. | C: Nitrogen |
| 4. A molecule formed by sharing of electrons [covalency] | D: Sodium |
| 5. A metallic atom having unstable electronic configuration. | E: Neutrons |
Define the term of atomic number.
Elements A, B and C have atomic numbers 9, 20 and 10 respectively.
- State which one is
(1) a non-metal,
(2) a metal,
(3) chemically inert.[A,B,C] - Write down the formula of the compound formed by two of the above elements.[BA2]
An element ‘A’ has mass number 23 and atomic number 11. State the –
- no. of neutrons in its shell,
- electronic configuration of the element ‘A’.
The atomic number and the mass number of an element is 26 and 56 respectively. Calculate the number of electrons, protons and neutrons in its atom. Draw the structure.
Mass No. 27 is for the element ______.
Match the following:
| Column A | Column B | ||
| 1. | K shell | a. | 8 |
| 2. | L shell | b. | 32 |
| 3. | M shell | c. | 2 |
| 4. | N shell | d. | 18 |
