The Periodic Table Flashcards
What is an energy level?
An energy level is defined as the fixed energy value that an electron in an atom may have
What is the ground state of an atom?
The ground state of an atom is one in which the electrons occupy the lowest available energy levels
What is the excited state of an atom?
The excited state of an atom is one in which the electrons occupy higher energy levels than those available in the ground state
What is heisenbergs uncertainty principle
Heisenberg’s uncertainty principle states that it is impossible to measure at the same time both the velocity and the position of an electron
What is an orbital?
An orbital is a region in space within which there is a high probability of finding an electron
What is a sublevel
A sublevel is a subdivision of a main energy level and consists of one or more orbitals of the same energy
What does an emission line spectrum consist of? What does it indicate?
It consists of coloured lines against a dark background. It indicates the presence of energy levels in atoms
What is the instrument used to examine spectra called? (2)
Spectrometers and spectroscopes
What did Bohr propose about orbits and energy levels?
That electrons revolve around the nucleus in fixed paths called orbits or energy levels
What did Bohr propose about the energy of an electron?
He proposed that the energy of an electron in an energy level is quantized i.e. fixed at a define amount
What happens to an atom when it absorbs energy?
It jumps from a lower energy level to a higher energy level
Energy is lost when an electron…
falls from a higher energy level to a lower energy level
Since on definite amounts of energy are emitted, this implies….
that electrons can occupy only definite energy levels
An absorption spectrum is produced when…
White light is passed through a gaseous sample of an element
An absorption spectrum consists of…
dark lines against a coloured background
What is an orbital?
an orbital is a region in space within which there is a high probability of finding an electron
S orbitals are …. shaped
spherical
P orbitals are …. shaped
dumbbell
What is a sublevel?
A sublevel is a subdivision of a main energy level and consists of one or more orbitals of the same energy
A Danish scientist called … provided much informations about the arrangement of electrons in atoms
Niels Bohr
A rainbow of colours is obtained when white light is passed through a …
glass prism
Each element has its own … emission line spectrum
To study spectra we use either a … or a …
spectrometer…spectroscope
A sample of a salt of sodium when heated gives off a … colour
An energy level is defined as …
Bohr stated that the energy of the electron is quantized. What does this mean?
The energy of the electron is fixed at a define amount
Energy is … when an electron falls from a higher energy level to a lower energy level.
In the equation E2-E1=hf what does the h stand for?
Distinguish between an emission spectrum and an absorption spectrum
State two limitations of Bohr’s theory that led to its modification.
Disinguish between an atomic orbital and a sublevel
What instrumental technique is based on the fact that each element has a unique atomic spectrum?
What does Heisenberg’s uncertainty principle say about an electron in an atom
Why is it possible for line emission spectra to be used to distinguish between different elements?
