Bohr Theory

Bohr's Model of the Atom


Niels Bohr (1913):


Niels Bohr (1913):-studied the light produced when atoms

were excited by heat or electricity




Rutherford's model couldn't explain why unique colours were obtained by atoms ofdifferent elements




Rutherford's model couldn't explain why unique colours were obtained by atoms ofdifferent elements

Bohr proposed that electrons are in orbits & when excited jump to a higher orbit. When they fall back to the original they give off light

Bohr's Model of the AtomBohr's model:

-electrons orbit the nucleus like planets orbit the sun



-each orbit can hold a specific maximum number of electrons



-each orbit can hold a specific maximum number of electrons

orbit maximum # electrons

1 22 83 8 4 18


Bohr's model:-electrons orbit the nucleus like planets

orbit the sun-each orbit can hold a specific maximum number of electrons-electrons fill orbits closest to the nucleus first.


e.g. fluorine:#P =

#e- =

#N =


e.g. fluorine:#P = atomic #

= 9#e- =

#N =


e.g. fluorine:#P = 9

#e- = # P = 9

#N =



#e- = 9

#N = atomic mass - # P = 10



#e- = 9

#N = 10draw the nucleus with protons & neutrons

9P10N



#e- = 9

#N = 10how many electrons canfit in the first orbit?

9P10N



#e- = 9

#N = 10how many electrons canfit in the first orbit?

2

9P10N



#e- = 9

#N = 10

how many electrons are left?

9P10N



#e- = 9

#N = 10

how many electrons are left? 7

9P10N



#e- = 9

#N = 10

how many electrons are left? 7how many electrons fit in the

second orbit?

9P10N



#e- = 9

#N = 10

how many electrons are left? 7how many electrons fit in the

second orbit? 8

9P10N



#e- = 9

#N = 10

9P10N


try these:

hydrogen

boron

magnesium


try these:

hydrogen1P0N


try these:

boron5P6N


try these:

magnesium

12P12N

Bohr Theory

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