<u>Answer:</u> The fraction of atom's mass contributed by nucleus is 0.99
<u>Explanation:</u>
Nucleons are defined as the sub-atomic particles which are present in the nucleus of an atom. Nucleons are protons and neutrons.
The isotopic symbol of Helium-4 atom is 
Number of electrons = 2
Number of protons = 2
Number of neutrons = 4 - 2 = 2
We are given:
Mass of He-4 atom = 
Mass of 1 electron = 
Calculating the mass contributed by the nucleus = 
Mass of the nucleus of He-4 atom = 
To calculate the fraction of atom's mass contributed by the nucleus, we use the equation:
Putting values in above equation, we get:
Hence, the fraction of atom's mass contributed by nucleus is 0.99
Explanation:
High density medium to low density medium.
<span>If a solution conducts electricity, it it positive evidence that solute dissolved in solvent is electrolyte.</span>
Answer: Option 1 and 11
1. Organic solvents are often flammable.
II. Organic solvents are often toxic.
Explanation:
Organic solvents are often flammable and Organic solvents are often toxic are the reasons why organic chemistry is a primary target of green chemistry because green chemistry is the use of principles or approach to remove hazardous or toxic substances from chemical.profuctd or processes to make them fit or safe for use and the solvents of organic chemist are toxic, therefore green chemistry remove the toxic substances.
