Chapter 2 - atoms Flashcards
What is the atomic theory
Theory that states all matter is composed of small units called atoms
List the individuals in the history of the atoms
Democritus, Dalton Thompson Rutherford Bohr Chadwick
What did Democritus do
Democritus introduced the idea of the atom as the basic building block matter. Democritus thought that atoms are tiny, uncuttable, solid particles that are surrounded by empty space and constantly moving at random.
What did dalton do
Discovered that atoms of are made up of smaller subatomic particles
- found out about protons
What did Thompson do
JJ Thompson found out about the electron
What did Rutherford do?
Theorised that the structure of atom was all subatomic particles clumped together in a ball shape
- plum pudding model
What Did Bohr do
Theorised and developed the structure of the atom used today
Called the Bohr model
What did Chadwick do
discovered the Neutron in atoms.
Neutrons are located in the center of an atom, in the nucleus along with the protons. They have neither a positive nor negative charge, but contribute the the atomic weight with the same effect as a proton.
Electrons, protons and neutrons
Neutron - elementary particle, has weight, neutral
Proton - positive charge in nucleus
Electrons - found outside in empty space in electron cloud, negative and orbits nucleus
Properties of a non metal
High ionization energies. High electronegativities. Poor thermal conductors. Poor electrical conductors. Brittle solids—not malleable or ductile. Little or no metallic luster. Gain electrons easily. Dull, not metallic-shiny, although they may be colorful.
Properties of a metalliod
usually look like metals
behave largely like nonmetals.
Physically, they are shiny, brittle solids with intermediate to relatively good electrical conductivity and the electronic band structure of a semimetal or semiconductor.
What is relative atomic mass
The average relative mass of an element naturally occurring is called a reactive atomic mass
What is relative isotopic mass
The mass of an individual isotope of each element compared to its standard is known as relative isotopic mass
What is relative isotopic abundance
The relative abundance of an isotope is the percentage of atoms with a specific atomic mass found in a naturally occurring sample of an element.
How to calculate Relative atomic mass?
(% x relative isotopic mass) + (% x relative isotopic mass)
Ar = —————————————————————————
100
What is a mass spectrometer?
A mass spectrometer is a device used to determine the relative isotopic masses of elements
What is a mass spectrum
A mass spectrum is the graph which graphically presents the information obtained by the mass spectrometer.
It plots relative abundance of each ion against its mass-to-charge ratio
M
—-
N
The steps of mass spectrometry
IADD
- Ionisation; the vaporised sample is bombarded with UV light or electrons to knock out the electrons, leaving atomic with positive charge
- Acceleration; the ions are then accelerated through a electric felid to get them all at the same speed
- Deflection: the ions pass through a magnetic field where they undergo deflection (lighter - more, heavy - deflect less)
- Detection: amount of ions that strike the detector and land in each position along detector shows the abundance of the specific isotope
- Data can be made graphically via a mass spectrum (y axis = abundance % and x axis = mass charge)
Uses of mass spectrometry
Quantitive measure
- separates the individual isotopes
- determines mass of each isotopes in sample of the element
- calculated the abundance’s of isotopes in sample
