Atoms may be regarded as comprising of protons,neutrons and electrons. If the mass attributed by electrons was doubled and that attributed by neutrons was halved, the atomic mass of C (mass number=12 atomic number=6)would be

(a)approximately the same

(b)doubled

(c)reduced approximately by 25%

(d)approximately halved

Asked by Yash Sahu | 9th Apr, 2014, 03:22: PM

Expert Answer:

(c) reduced approximately by 25% is the  correct option.
The mass of electron is negligible.
Atomic mass = mass of protons + mass of neutrons
                   = 6 + 6
                    =12
If the mass of neutons is halved, then atomic mass = 6+3=9
Now 9 is approximately 25% of 12. Hence, the correct option is (c)

Answered by  | 9th Apr, 2014, 04:50: PM

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