Question

1.Why neutron was discovered late?
2. Why gold foil was used in Rutherford experiment?
3.write significance of mass no. ?
Plzzzzz fast

Answer 1

⏺heya friend !

✔here's your answer ;-

〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰

Q1 ) Why neutron was discovered late?

➡answer :-
⚫as you know, proton and electron both contain positive and negative charges respectively so they were able to be discovered early.
⚫but , in case of neutron it contains no charge , hence its detection was quite hard because there was no way as how to detect its presence .
⚫it is assumed that neutron is a neutal particle but yet they cannot property describe it.

Q2 ) Why gold foil was used in Rutherford experiment?

➡answer :-
⚫as gold is the most malleable metal so it can be beaten into sheets .
⚫Rutherford wanted the thinnest layer as possible for conducting his experiment.
⚫the goldsheet was approximately around 1000 atoms thick only.
⚫hence, gold foil was selected by Rutherford for his alpha scattering experiment.

Q3 ) write significance of mass no. ?

➡answer :-
⚫mass number is the total number of protons and neutrons ( or collectively called nucleons) in an atomic nucleus.
⚫its significance is that it determines the atomic mass of atoms.
⚫The mass number is different for each different isotope of a chemical element.
⚫The mass number is written either after the element name or as a superscript to the left of an element's symbol. 

** ISOTOPE :- they are the elements which have sane atomic number but different mass number.

▶▶▶▶▶▶▶▶▶▶▶▶▶▶▶

i hope it helps u !!!☺

Answer 2

hi friend
here's your answer looking for

☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣

let's answer your all questions one by one.

Question 1:- Why neutron was discovered late?

Answer :- as a neutrons have the neutral charge means that they didn't have any type of charge. so, it was too easy to find the particles that is charged.

so electron and proton where found earlier than the neutron.

actually, after the discovery of protons and electrons, there was the discovery of isotopes. isotopes are the atoms of same element having the different masses or elements having same atomic number but different masses.

so, these different masses shows , there must be some neutral particles that are also present in the atom , that has the same mass as protons.

so from this the neutrons where discovered.
and that is the reason why the neutrons were discovered late.

Question 2 :- Why gold foil was used in Rutherford experiment?

Answer:- as we know that the gold is one of the most malleable metal.
so that can be drawn into thin sheets very easily.

and as in the experiment of Rutherford, he wants to make the Alpha particle pass through it easily.
actually , he want the average thickness of 1000 atoms of that gold foil.

so on seeing it's malleability property , that can be drawn into thin sheets , he chooses the gold foil.
and as a result he was surprised to see that, some of the Alpha particle get passed through the point where as some shows deflection.

Question 3:- write significance of mass no. ?

Answer :- the atomic mass of an atom is nothing but it is the number of proton and neutron present in its nucleus.

here you might be wondering why the electron mass is not taken in atomic mass.
so let me tell you that, the electrons have mass but it is negligible.
so, on calculating the total mass of an atom along with electrons will produce a negligible difference, that's why the electron is not calculated in atomic mass of an atom.

so,
atomic mass = no. of protons + no. of nutrons.

don't confuse between the atomic mass and atomic number.
so let me explain you both.
as I have already explained you about atomic mass so I am going to explain you atomic number.

Atomic number :- atomic number of an atom is nothing but it is the number of protons present in the nucleus of an atom.

For example :- if you take the example of a Helium atom. then you will find that it has 2 protons and 2 neutrons in its nucleus.

so
Helium has atomic mass=number of protons + number of neutrons= 2+2=4units
and it has the atomic number= no. of protons =2

☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣☣
hope you are satisfied in my answer if you have any problem then you can contact me
from brainly benefactor
Amaytripathi19