Atoms Flashcards
Who discovered e-
J.J.Thomson
What is the name of first atomic model
Who gave the first atomic model
Plum pudding model
J.J.Thomson
which experiment did rutherford did
Alpha particle scattering
How was alpha particle experiment done
A beam of 5.5 Mev emitted from Bi atom was fallen into gold foil.
The striking of e- on ZnS screen produced light flashes which was visible through a microscope
What are the observations came from alpha particle experiment
1 Atom has a very small dense and +vely charged nucleus
2 Nucleus is present in the center of atom
3 Most of the alpha particles went undeviated
4 Most of the atom is empty space
Who discovered nucleus
Rutherford
Explain Rutherford’s Nuclear Model
1 The entire +ve charge and mass is concentrated in the nucleus
2 e- move around nucleus in an orbit
3 The size of nucleus is approx 10^-15 to 10^-14 m
4 e- are at a distance of 10,000 to 100,000 times the size of nucleus
5 Most of the atom is empty space
What are alpha particles
Nuclei of a Helium atom are alpha particles
Charge on alpha particles is 2e
Why gold foil was taken in alpha particle scattering
Because nucleus of gold is about 50 times heavier than alpha particles so it is reasonable to take that gold nucleus remains stationary
What is force b/w alpha particle and nucleus of gold atom
F = (K x 2e x Ze)/r^2
What is impact parameter
it is the perpendicular distance of the initial velocity vector and alpha particle from the center of nucleus
What is emission line spectrum
When atomic gas is excited at low pressure , by passing electric current through it the emitted radiation has a specific wavelength
A spectrum of this kind is known as emission line spectrum
what is absorption spectrum
If their electrons in the ground level jump to an immediate higher energy level, absorbing energy will result in a continuous spectrum with dark lines, which is known as an absorption spectrum.
What are spectral lines
A spectral line is a dark or bright line in an uniform and continuous spectrum, resulting from the emission or absorption of light
Give Bohr postulates
1 e- in a atom can revolve in a certain stable orbits without the emission of radiant energy
2 e- revolves around the nucleus only in those orbits for which angular momentum is integral multiple of h/2pi
L = nh/2pi
3 When e- make a transition from one orbit to another lower energy orbit a photon is emitted having energy equal to the energy difference b/w initial and final state
h x v = Ei-Ef
