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प्रश्न
State the term for the following:
The amount of substance which contains the same number of units as the number of atoms in carbon-12.
उत्तर
mole
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संबंधित प्रश्न
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
From the symbol `""_15^31"P"`, state :
(i) mass number of phosphorus,
(ii) atomic number of phosphorus, and
(iii) electron configuration of phosphorus.
The atomic number and mass number of sodium are 11 and 23 respectively. What information is conveyed by this statement?
Match the atomic numbers 4,8,10,15 and 19 with the following:
Element with 6 valence electrons
If an atom ‘A’ has atomic number 19 and mass number 39, state –
- Its electronic configuration.
- The number of valence electrons it possesses.
Complete the following table.
| Atomic Number | Mass Number | Number of Neutrons | Number of Protons | Number of Electrons | Name of the Element |
| 9 | ______ | 10 | ______ | ______ | ______ |
| 16 | ______ | 16 | ______ | ______ | ______ |
| ______ | 24 | ______ | ______ | 12 | Magnesium |
| ______ | 2 | ______ | 1 | ______ | ______ |
| ______ | 1 | 0 | 1 | 1 | ______ |
Name the 3 sub-atomic particles of an atom.
The Atomic number of an element is 20. It has ______ valence electrons.
K and L shells can accommodate a maximum of 2 and 8 electrons respectively.
In which one of the following, the number of protons is greater than the number of neutrons but number of protons is less than the number of electrons?
