What were the observations that made us look for the existence of neutrons?
What were the observations that made us look for the existence of neutrons?
The correct options are
B The existence of forms of same element but with different mass (Isotopes).
C Helium's atomic number was 2 but was 4 times heavier than Hydrogen.
"Different nuclei have different masses" This statement doesn't give any reason to look for neutrons; as more protons will increase the mass of the atom, right!!!!!
But same element existing in different form with different masses is a reason.
Like carbon has 2 forms. Both have same atomic number, which means that number of protons in both are same, but still their masses are different.
So there has to be something other than protons that give mass to them.
Also Helium has double the atomic number than hydrogen. We knew this because Helium has only 2 electron so to make it stable we will need 2 protons.
Hydrogen has one electron we knew, so to balance the charge we will need just one proton. Now if the mass of atom is equal to the mass of protons in it (mass of electron is negligible w.r.t. the mass of proton) then by that argument Helium should be twice as heavy as Hydrogen atom (as He has 2 protons while H has 1).
But practically we see that He weighs 4 times more than H atom. So this also led scientist to believe in the existence of neutron.
Neutron star. If neutron is not known, then how will we name something neutron star? : p
B
The existence of forms of same element but with different mass (Isotopes).
C
Helium's atomic number was 2 but was 4 times heavier than Hydrogen.
"Different nuclei have different masses" This statement doesn't give any reason to look for neutrons; as more protons will increase the mass of the atom, right!!!!!
But same element existing in different form with different masses is a reason.
Like carbon has 2 forms. Both have same atomic number, which means that number of protons in both are same, but still their masses are different.
So there has to be something other than protons that give mass to them.
Also Helium has double the atomic number than hydrogen. We knew this because Helium has only 2 electron so to make it stable we will need 2 protons.
Hydrogen has one electron we knew, so to balance the charge we will need just one proton. Now if the mass of atom is equal to the mass of protons in it (mass of electron is negligible w.r.t. the mass of proton) then by that argument Helium should be twice as heavy as Hydrogen atom (as He has 2 protons while H has 1).
But practically we see that He weighs 4 times more than H atom. So this also led scientist to believe in the existence of neutron.
Neutron star. If neutron is not known, then how will we name something neutron star? : p
