Chapter One: Atomic Structure Flashcards
Electron weight
1/1800 of a proton
Are electrons and protons electrostatic?
Yes
What is Bohr’s model?
Discovered in 1913 it is the structure that suggested that electrons orbited around the nucleus in definite paths called shells
What is the most current model of the atom
Schrodinger
Ion
An atom that has either lost or gained an electron
Cation
Have lost electrons so they end up with a positive charge
Anion
Gained electrons so they have a negative charge
Macromolecules and examples
A very large molecule ie; synthetic polymers, proteins and DNA
Nanometre
Is 1 billionth of a metre
Conversion table
1m = 10^2cm = 10^3mm = 10^6micro = 10^9nm 1nm = 10^-9m = 10^-6cm
What is nanotechnology?
Is working with technology at a nanoscale to create a cleaner, safer, longer lasting and smarter products for the future.
What does nanoscience deal with?
Directly with atoms, molecules and macromolecules
Energy properties
Energy is not continuous but comes in quanta and particles have wave properties.
Quanta
Small packets of energy
Molecular manufacturing
When scientists assemble materials atom by atom, to make atoms into specific molecules and create a specific product.
Isotope
Atoms of the same element that have different numbers of neutrons
Isotope properties
Have similar chemical properties due to electron structure
Have different physical properties due to their different masses
Aufbau’s rule
In ground state electrons fill orbitals of lowest energy level before occupying higher energy levels.
Ground state
Electrons are in their most stable configuration
Hund’s rule
Every orbital in a subshell is singly occupied with one electron before any one orbital is doubly occupied.
Filling subshells rule
Fully filled subshells are more stable than half filled subshells which are more stable than partially filled subshells
What causes colour in fire?
Is the way the electrons are arranged around the nucleus of an atom
What does arrangement of electrons determine?
The properties and behaviour of elements and the materials made from them
What happens when a white light is passed trhough a prism?
It creates a continuous spectrum of colour
Why does an element emit light when heated?
Becuase the atoms absorb energy then when they return to ground state they release the energy as light.
How do you create an emission spectrum
By passing the light emitted by an element through a prism.
What does an emission spectrum show?
The lines correspond to the energy difference between electron shell levels
What is the difference between a continuous spectrum and the emission spectrum?
The continuous spectrum is formed when a light is passed through a prism whereas the emission spectrum is the light emitted from an element that has been passed through a prism.
Excited electrons in Bohr’s model
In Bohr’s model the electron float around an orbit of the nucleus in their specific energy levels, then they jump from their ground state up to the next shell and when they return the energy released is produced as light
How can you identify an element based on the light it releases?
Because there are only specific energy levels released they correspond to a line on the emission spectrum.
Shells capacity
2n^2 (n is the shell)
The outer shell never has more than 8 electrons in the first 20 elements
What are the limitations of Bohr’s model?
The electrons don’t actually travel in paths
The filling order has exceptions
When and who discovered the quantum theory?
Erwin Schrodinger in 1926
What is the Quantum Mechanical Model?
Is a complex mathematical model based on particles such as electrons showing wave like behaviour
What makes up the Quantum Mechanical Model?
Shells, subshells and orbitals
Shells
Shell 2, shell 3 etc
Subshells
s,p,d,f
Shell 2 = 2 subshells
Orbitals
What make up the subshells
Plum pudding model
Sir J.J Thompson suggested that an atom is a positively charged sphere that had electrons embedded in the sphere discovered in 1897
Subatomic particles
Electrons
Neutrons
Protons
Molecules
Are substances that consist of 2 or more atoms chemically combined
The types of atoms, size, arrangement and shape significantly impact the properties of materials
Potential risks of nanotechnology
Miniaturised weapons
Designing biological organisms
Excited states
When an atom moves to a higher energy level than the ground state by absorbing energy
The outermost energy electron moves to a higher subshell
Exceptions to the filling rule
Chromium 24 and copper 29
chromium fills to 3d^5
copper fills to 3d^10
Stability of shells
Filled shells are more stable than half filled shells which are more stable than partially filled shells
Schrodinger’s model
Proposed that electrons would move around in regions of space called orbitals
Max. electrons a subshell can hold
s - 2
p - 6
d - 10
f - 14
How many electrons in an orbital?
0, 1 or 2
