Introduction to Excited Elements
Lab
ACOS 3.0 Use the periodic table to identify periodic
trends, including atomic radii, ionization energy,
electronegativity, and energy levels.
ACOS 3.3 Utilizing benchmark discoveries to describe
the historical development of atomic structure,
including photoelectric effect, absorption, and
emission spectra
Introduction
• Scientists observed that certain elements
emitted visible light when heated in a flame.
• Analysis revealed the element’s chemical
behavior is related to the arrangement of
electrons in its atom.
– Visible Light: A form of electromagnetic radiation.
Electromagnetic Spectrum
• Contains all forms of electromagnetic
radiation.
• The only differences in the forms are their
wavelength & frequency.
Atomic Emission Spectra
• The set of frequencies of electromagnetic
waves emitted by atoms of the element.
• Consists of several individual lines (Bands) of
color
• Each element’s atomic emission spectrum is
unique
• This spectrum can be used to determine what
element you are viewing
Ground State
• Ground State- the lowest allowable energy
state of an atom. n=1 (The atom does not
radiate energy)
– When energy is added to the atom it goes up to a
higher-energy orbital such as n=2
• Up to 7 energy levels have been found for the
hydrogen atom. Meaning n values can range
from 1-7.
Energy Levels
• The smaller the electron’s orbit, the lower its
energy state, or level.
• Each energy level has a quantum number, n,
applied to it. (ladder rungs)
What causes this light?
•As electrons absorb energy they become
excited and move to higher energy levels.
•This energy is released in set amounts of
energy (quanta) as the electrons fall back into
lower energy levels.
•This energy is released in many regions of the
electromagnetic spectrum, including the visible
region that you can see.
•Quanta of light energy is called photons.
- Electrons of atoms can be excited in various
ways including: heat, electricity, and friction.
Spectral lines are created by energy released as an
-Spectral
lines
are
by energy
electron
moves
from
ancreated
excited state
to a lower
released as an electron moves from an
state.
excited state to a lower state.
References
• http://www.antonineeducation.co.uk/physics_gcse/Unit_1/Topic_5
/em_spectrum.jpg