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प्रश्न
Multiple Choice Questions
The sum of number of protons and number of neutrons present in the nucleus of an atom is called its
पर्याय
mass number
atomic number
number of electrons
all of the above
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उत्तर
mass number
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संबंधित प्रश्न
What are the two main features of Rutherford’s atomic model?
What is variable valency? Name two elements having variable valency and state their valencies.
Tick the most appropriate answer.
Which of these have similar chemical properties but different set of physical properties and mass number?
- isobars
- elements
- isotopes
- none of these
State the main postulates of Dalton’s atomic theory.
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 |
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]
Explain the following terms.
- Proton
- Electron
- Neutron.
Electrons revolve around the nucleus in definite open shells.
K and L shells can accommodate a maximum of 2 and 8 electrons respectively.
A group of elements in the periodic table is given below (Boron is the first member of the group and Thallium is the last).
Boron, Aluminium, Gallium, Indium, Thallium
Answer the following question in relation to the above group of elements:
The atomic number of boron is 5. Write the chemical formula of the compound formed when boron reacts with chlorine.
