Answer: 68
Explanation:
Isotopes of an element have same number of protons but different number of neutrons. Which means isotopes of an element have same atomic number but different mass number.
Atomic number is equal to the number of protons or the number of electrons for a neutral atom and is specific to a particular element.
Mass number is the sum of number of protons and the number of neutrons.
Given : atomic number of element Q = 68 = number of protons
Mass number of isotope Q-136 = 136
But as isotopes have same atomic number, the number of protons will be same and hence there are 68 protons are in a neutral atom of this isotope.
The proper science is validated by Experimentation and Testing .
What is experiment and testing?
Experiment is performed to support or Refuge a hypothesis which is given by someone.
Test is to figure out what we expect and what we have observed.
So , the proper validation of science is Experiment and testing because science is all about hypothesis, discoveries if want to prove them right or wrong we have to perform experiment and test .
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