Elements of Life Flashcards
What are the 3 subatomic particles?
Protons
Neutrons
Electrons
What is the charge and mass of a proton?
Charge: +1
Mass: 1
What is the charge and mass of a neutron?
Charge: 0
Mass: 1
What is the charge and mass of an electron?
Charge: -1
Mass: 0.00055
What information is shown about elements on the periodic table? and what does this tell us?
The mass number: Protons + neutrons
The atomic number: Protons
The name of the element
What is an isotope?
It is atoms of the same element that have different number of neutrons in the nucleus.
What decides what element an atom is?
The number of protons in the nucleus
What is the relative atomic mass?
This is the average mass of the different isotopes of an element taking into account their abundance
What is mass spectrometry?
It is a method of measuring the atomic/molecular masses of different particles in a sample and their relative abundances
How does mass spectrometry work?
Sample atoms/molecules get ionised and form positive cations. They are then separated according to their mass to charge ratio (m/z)
What is nuclear fusion?
This is when two light atomic nuclei fuse together to form a single heavier nucleus.
What is required for nuclear fusion?
The nuclei must come very close together. It only occurs at high temperatures and pressures where atoms collide with lots of energy so this repulsion is overcome
What is the equation for the fusion of 1,1Hydrogen with 2,1Hydrogen?
1,1Hydrogen + 2,1Hydrogen ==> 3,2Helium + Energy
Energy is released
What is an absorption spectra? and what does it look like?
It shows what frequencies of light are absorbed by a substance. It is a rainbow coloured spectrum with black lines at the frequencies that have been absorbed
What is an emission specrta? and what does it look like?
It shows the frequencies of light that have been emitted from a substance. It is a black coloured spectrum with coloured lines that show what frequencies have been emitted
What is Bohr’s theory of wave particle duality?
The behaviour of light can only be explained as it being both a wave and a particle.
What are two characteristic properties of a wave?
The wavelength and the frequency
What is the equation relating frequency and wavelength?
C = λ x ν C = Speed of light (3x10^8) λ = Wavelength ν = Frequency
What is a photon?
It is a tiny packet of energy. Light is considered to be a stream of photons.
What affects the energy of a photon? and what is the equation relating the two?
The frequency affects the energy of a photon. E = hν E = Energy h = Planks constant ν = Frequency
What is Bohr’s theory?
It explains why atoms only emit light of certain frequencies
When an atom absorbs a photon their electrons are excited and jump to a higher energy level. This produces an absorption spectrum. Later electrons drop back down to their original energy level and a photon is released. This produces an emission spectra.
What does Bohr’s theory show?
It shows why we get emission and absorption spectra
It gives us a model for the atom:
- The energy of a photon is equal to the distance between two energy levels
- Electrons in atoms exist in specific energy levels
What does quantised mean when it comes to the energy levels of an atoms?
It means that the energy levels are specific and so electrons can not be at any energy value, just the values that are allowed.
What is the flame test colour for Lithium?
Bright Red
What is the flame test colour for Sodium?
Yellow
What is the flame test colour for Potassium?
Lilac