ATOMIC
SPECTRA
TOPIC
ATOMIC SPECTRA
EXPLANATION
ATOMIC SPECTRA ARE FORMED WHEN
ELECTRONS IN AN ATOM MOVE BETWEEN
QUANTIZED ENERGY LEVELS. WHEN AN
ELECTRON ABSORBS ENERGY, IT JUMPS TO A
HIGHER LEVEL (EXCITED STATE). WHEN IT
RETURNS TO A LOWER LEVEL, IT EMITS A
PHOTON OF ENERGY EQUAL TO THE
DIFFERENCE BETWEEN THE TWO LEVELS.
THIS EMITTED PHOTON HAS ENERGY
E = HF = EI – EF
SINCE THE ENERGY LEVELS ARE FIXED, ONLY
SPECIFIC WAVELENGTHS ARE PRODUCED. THIS
GIVES RISE TO LINE SPECTRA, NOT CONTINUOUS
SPECTRA.
EACH ELEMENT HAS ITS OWN UNIQUE LINE
SPECTRUM BECAUSE ITS ENERGY LEVELS ARE
DIFFERENT.
, ATOMIC
SPECTRA
NET QUESTIONS
ATOMIC SPECTRA CONSIST OF
A. CONTINUOUS SPECTRUM
B. LINE SPECTRUM
C. BAND SPECTRUM
D. BROAD SPECTRUM
CORRECT ANSWER B.
BALMER SERIES LIES IN THE
A. INFRA-RED REGION
B. VISIBLE REGION
C. ULTRAVIOLET REGION
D. X-RAY REGION
CORRECT ANSWER B.
THE LYMAN SERIES CORRESPONDS TO
ELECTRON TRANSITIONS TO
A. N = 1
B. N = 2
C. N = 3
D. N = 4
CORRECT ANSWER A.
, ATOMIC
SPECTRA
TOPIC
X-RAYS
EXPLANATION
X-RAYS ARE HIGH-FREQUENCY ELECTROMAGNETIC
WAVES WITH VERY SHORT WAVELENGTH. THEY ARE
PRODUCED WHEN HIGH-SPEED ELECTRONS STRIKE A
HEAVY METAL TARGET SUCH AS TUNGSTEN. INSIDE THE
X-RAY TUBE, ELECTRONS ARE ACCELERATED BY A HIGH
VOLTAGE AND THEN SUDDENLY DECELERATED ON
HITTING THE TARGET, PRODUCING X-RAYS.
TWO TYPES OF X-RAYS ARE PRODUCED.
CONTINUOUS X-RAY SPECTRUM IS PRODUCED DUE TO
SUDDEN DECELERATION OF ELECTRONS.
CHARACTERISTIC X-RAY SPECTRUM IS PRODUCED
WHEN INNER-SHELL ELECTRONS OF THE TARGET ATOM
ARE EJECTED AND OUTER ELECTRONS FALL TO FILL THE
VACANCY.
THE MINIMUM WAVELENGTH OF X-RAYS DEPENDS ONLY
ON THE ACCELERATING VOLTAGE AND IS GIVEN BY
ΛMIN = HC / EV
X-RAYS ARE HIGHLY PENETRATING AND ARE USED IN
MEDICAL IMAGING, INDUSTRY, AND CRYSTAL STRUCTURE
ANALYSIS.
SPECTRA
TOPIC
ATOMIC SPECTRA
EXPLANATION
ATOMIC SPECTRA ARE FORMED WHEN
ELECTRONS IN AN ATOM MOVE BETWEEN
QUANTIZED ENERGY LEVELS. WHEN AN
ELECTRON ABSORBS ENERGY, IT JUMPS TO A
HIGHER LEVEL (EXCITED STATE). WHEN IT
RETURNS TO A LOWER LEVEL, IT EMITS A
PHOTON OF ENERGY EQUAL TO THE
DIFFERENCE BETWEEN THE TWO LEVELS.
THIS EMITTED PHOTON HAS ENERGY
E = HF = EI – EF
SINCE THE ENERGY LEVELS ARE FIXED, ONLY
SPECIFIC WAVELENGTHS ARE PRODUCED. THIS
GIVES RISE TO LINE SPECTRA, NOT CONTINUOUS
SPECTRA.
EACH ELEMENT HAS ITS OWN UNIQUE LINE
SPECTRUM BECAUSE ITS ENERGY LEVELS ARE
DIFFERENT.
, ATOMIC
SPECTRA
NET QUESTIONS
ATOMIC SPECTRA CONSIST OF
A. CONTINUOUS SPECTRUM
B. LINE SPECTRUM
C. BAND SPECTRUM
D. BROAD SPECTRUM
CORRECT ANSWER B.
BALMER SERIES LIES IN THE
A. INFRA-RED REGION
B. VISIBLE REGION
C. ULTRAVIOLET REGION
D. X-RAY REGION
CORRECT ANSWER B.
THE LYMAN SERIES CORRESPONDS TO
ELECTRON TRANSITIONS TO
A. N = 1
B. N = 2
C. N = 3
D. N = 4
CORRECT ANSWER A.
, ATOMIC
SPECTRA
TOPIC
X-RAYS
EXPLANATION
X-RAYS ARE HIGH-FREQUENCY ELECTROMAGNETIC
WAVES WITH VERY SHORT WAVELENGTH. THEY ARE
PRODUCED WHEN HIGH-SPEED ELECTRONS STRIKE A
HEAVY METAL TARGET SUCH AS TUNGSTEN. INSIDE THE
X-RAY TUBE, ELECTRONS ARE ACCELERATED BY A HIGH
VOLTAGE AND THEN SUDDENLY DECELERATED ON
HITTING THE TARGET, PRODUCING X-RAYS.
TWO TYPES OF X-RAYS ARE PRODUCED.
CONTINUOUS X-RAY SPECTRUM IS PRODUCED DUE TO
SUDDEN DECELERATION OF ELECTRONS.
CHARACTERISTIC X-RAY SPECTRUM IS PRODUCED
WHEN INNER-SHELL ELECTRONS OF THE TARGET ATOM
ARE EJECTED AND OUTER ELECTRONS FALL TO FILL THE
VACANCY.
THE MINIMUM WAVELENGTH OF X-RAYS DEPENDS ONLY
ON THE ACCELERATING VOLTAGE AND IS GIVEN BY
ΛMIN = HC / EV
X-RAYS ARE HIGHLY PENETRATING AND ARE USED IN
MEDICAL IMAGING, INDUSTRY, AND CRYSTAL STRUCTURE
ANALYSIS.
