13.
Let mass of electron is half, mass of proton is two
times and mass of neutron is three fourth of orignal.
The find out new atomic wt. of O 16 atom :-
(1) increases by 37.5%
(2) Remain constant
(3) increases by 12.5%
(4) decreases by 25%
Answers
Explanation:
The mass of electron is negligible as compared to that of proton and neutron. Therefore we will neglect the change in the mass of electron.
Mass of proton is 1 amu and mass of neutron is 1 amu.
Oxygen atom contains 8 protons and 8 neutrons.
Mass of O atom = 8p + 8n
Mass of O atom = 8 x 1 amu + 8 x 1 amu = 16 amu
Original mass of O atom is 16 amu.
Mass of proton becomes two times of its original.
Therefore new mass of proton is 2 amu
Mass of neutron changes to 3/4 of its original.
Therefore new mass of neutron is 0.75 amu.
New mass of O atom = 8p + 8n
New mass of O atom= 8x 2amu + 8 x 0.75 amu
New mass of O atom = 22 amu.
The new mass of oxygen atom would be 22 amu.
% increase in the mass can be calculated as
% increase = Change in mass / Original mass
% increase =
% increase = 37.5%
The mass will increase by 37.5%
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