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प्रश्न
Differentiate between the following term:
Atomic number and mass number
उत्तर
Differentiate between:
Atomic number:
- Z is the number of protons or the number of electrons in an atom.
- Present in nucleus = P
Present in orbits = e
Mass number:
- A is the sum of protons and neutrons.
- Present in the nucleus of an atom.
APPEARS IN
संबंधित प्रश्न
Give the following a suitable word/phrase.
Atoms of same element with same atomic number but a different mass number.
State the mass number, the atomic number, number of neutrons and electronic configuration of the following atoms.
`""^12""_6C, ""^16""_8O, ""^19""_9F, ""^20""_10Ne, ""_13""Al""^27, ""_17""Cl""^35`
Also, draw atomic diagrams for them.
Fill in the following blanks in respect of an atom of an element
| No. of protons | No. of neutron | Mass number | Atomic number | No. of electrons | Symbol |
| 11 | 12 | ___________ | ___________ | ___________ | ________ |
Match the atomic numbers 4,8,10,15 and 19 with the following:
Element with 6 valence electrons
Draw the atomic diagram of the following element showing the distribution of – protons, neutrons and the electrons in the various shell of the atom.
Phosphorus – \[\ce{^31_15P}\]
[The upper number represent the – mass number and the lower number represent the – atomic number e.g. calcium – mass number = 40, atomic number = 20]
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 |
The diagram represents an isotope of hydrogen [H]. Answer the following:
Atomic no. = 1
Mass no. = 1
Do isotopes have the same atomic number or the same mass 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]
The Atomic number of an element is 20. It has ______ valence electrons.
Mass No =______ + No. of Neutrons.
