Helium is the lightest noble gas and the second most abundant element (after hydrogen) in the universe. the mass of a helium−4 atom is 6.64648 × 10−24g, and each of its two electrons has a mass of 9.10939 × 10−28g. what fraction of this atom's mass is contributed by its nucleus?

The fraction of atom's mass contributed by nucleus is 0.99

Explanation:

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

i think it's c. i'm not sure but i think so.

answer:

the reaction is type of combination reaction.

explanation:

on the product side, there are 2 molecules of bonded to fe   which means one atom of fe are combined two molecules of . so, balanced chemical equation becomes :

this reaction follows the reaction type of combination reaction. a combination reaction is defined as chemical reaction in which reactants combines together to form a single product.