Atomic Structure, Chemical Bonding & Solutions
Atomic Structure : John Dalton in 1803 put forward his atomic theory which states that
– an atom is the simplest integral particle of the matter that takes part in chemical
reaction.
However, modern researchers have conclusively proved that, atom is no longer an
indivisible and indestructible particle. It has been broken in to smaller fragments like
electrons, protons and neutrons. Although an atom is extremely small, it has a definite
complete structure. Modern atomic structure is based mainly on Rutherford’s scattering
experiment on atoms.
Rutherford’s Experiment: Rutherford carried out his experiment by bombarding a
very thin gold foil 0.0004 mm with high speed α particles (He2+) emitted from Radium.
Observations:
1) Majority of α-particles continued their straight path without any deflection.
2) Some particles deflected from their path through large angles.
3) Very few of them returned (1 in 20,000) in opposite direction.
Conclusions:
1) The atom is largely an empty space, since most of α particles pass through the atom.
2) The fact that very few α particles returned in opposite direction, suggests that, whole
of
positive charge and mass is concentrated at the central point of negligible space called
nucleus.
3) The negatively charged electrons remain outside of the nucleus at relatively large
distance and are moving in orbits around the nucleus like planet around the sun.
Rutherford’s Atomic Model:
1) Nucleus: It is a small positively charged part of the atom. It is situated at the centre
and carries almost entire mass of the atom. Nucleus contains neutrons and protons.
2) Extra Nuclear Part: This part is empty part of the atom. In this part electrons revolve
at very high speed in fixed path, called orbits or shells.
Atomic Structure : John Dalton in 1803 put forward his atomic theory which states that
– an atom is the simplest integral particle of the matter that takes part in chemical
reaction.
However, modern researchers have conclusively proved that, atom is no longer an
indivisible and indestructible particle. It has been broken in to smaller fragments like
electrons, protons and neutrons. Although an atom is extremely small, it has a definite
complete structure. Modern atomic structure is based mainly on Rutherford’s scattering
experiment on atoms.
Rutherford’s Experiment: Rutherford carried out his experiment by bombarding a
very thin gold foil 0.0004 mm with high speed α particles (He2+) emitted from Radium.
Observations:
1) Majority of α-particles continued their straight path without any deflection.
2) Some particles deflected from their path through large angles.
3) Very few of them returned (1 in 20,000) in opposite direction.
Conclusions:
1) The atom is largely an empty space, since most of α particles pass through the atom.
2) The fact that very few α particles returned in opposite direction, suggests that, whole
of
positive charge and mass is concentrated at the central point of negligible space called
nucleus.
3) The negatively charged electrons remain outside of the nucleus at relatively large
distance and are moving in orbits around the nucleus like planet around the sun.
Rutherford’s Atomic Model:
1) Nucleus: It is a small positively charged part of the atom. It is situated at the centre
and carries almost entire mass of the atom. Nucleus contains neutrons and protons.
2) Extra Nuclear Part: This part is empty part of the atom. In this part electrons revolve
at very high speed in fixed path, called orbits or shells.
