Advertisements
Advertisements
प्रश्न
Explain the need for a reference atom for atomic mass. Give some information about two reference atoms.
उत्तर
- Mass of an atom is concentrated in its nucleus. It is the sum of proton(p) and neutron(n). The number (p + n) is called atomic mass number.
- Therefore, the concept of reference atom for atomic mass is taken into consideration.
Initially hydrogen atom being lightest was chosen as the reference atom. The relative mass of hydrogen atom was accepted as (1). this is how relative atomic masses of various elements were determined in reference of hydrogen. For example: the mass of one nitrogen atom is fourteen (14) times that of a hydrogen atom. - In 1961, the carbon atom was selected as the reference atom. In this method, the relative mass of one atom of carbon was accepted as 12. The relative mass of a hydrogen atom compared to a carbon atom is `12 xx 1/12` i.e. 1 u.
- On the relative masses of atoms, the mass of a proton and a neutron is approximately 1.
APPEARS IN
संबंधित प्रश्न
How many atoms are present in one gram atomic mass of a substance ?
Define gram atomic mass of a substance. How much is the gram atomic mass of oxygen ?
What is meant by saying that 'the atomic mass of oxygen is 16' ?
Define the term:
Mass number
A hydrocarbon contains 4.8g of carbon per gram of hydrogen. Calculate the gram atom of each.
Explain the following:
An element has atoms with different mass numbers.
Define the term of mass number.
Select the correct answer from the answer in the bracket to complete the sentence.
An element has electronic configuration 2, 8, 1 and 12 neutrons. Its mass no. is ________.
Select the correct answer from the answer in the bracket to complete the sentence.
An atom with electronic configuration 2, 7 and mass number 19 will have ________ neutrons.
Relative atomic mass is otherwise known as ______.
Answer the following question using the data given below:
- Assertion: The Relative Atomic mass of aluminium is 27
- Reason: An atom of aluminium is 27 times heavier than 1/12th of the mass of the C – 12 atom.
Calculate the % of each element in calcium carbonate. (Atomic mass: C-12, O-16, Ca -40)
One electron is present in the outermost shell of the atom of an element X. What would be the nature and value of charge on the ion formed if this electron is removed from the outermost shell?
Chlorine exists in two isotopic forms, \[\ce{Cl-37}\] and \[\ce{Cl-35}\] but its atomic mass is 35.5. This indicates the ratio of \[\ce{Cl-37}\] and \[\ce{Cl-35}\] is approximately
An atom having atomic mass number 13 has 7 neutrons. What is the atomic number of the atom?
