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प्रश्न
Name the following:
An element having valency 'zero'
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उत्तर १
Helium
उत्तर २
Element He, Ne, Ar i.e. Noble gases have ‘zero’ valency.
संबंधित प्रश्न
(i) How many atoms of each kind are present in the following molecules: calcium oxide, chlorine, water, carbon tetrachloride?
(ii) How many electrons are required for their octet structure?
Name an element which does not contain neutron.
Why do they exist as monoatoms in molecules?
Name the following:
Two atoms having the same number of protons and electrons but different number of neutrons.
Explain
Duplet rule for the formation of hydrogen
Potassium (at No.19) and chlorine (at No.17) react to form a compound. Explain the formation of the compound on the basis of oxidizing agent.
Give the orbital diagram of the following:
Magnesium chloride
Copy and complete the following table relating to the atomic structure of some elements:
| Element | Atomic Number | Mass Number | Number of protons | Number of Neutrons | Number of Electrons |
| Beryllium | 4 | 9 | |||
| Fluorine | 9 | 10 | |||
| Sodium | 12 | 11 | |||
| Aluminium | 27 | 13 | |||
| Phosphorus | 31 | 15 |
Choose the odd one out and write the reason:
Elements A, B and C have atomic number 17, 19 and 10 respectively.
State which one is chemically inert.
