Chapter 1 & 2 Flashcards
Isotope
Atoms of the same element with different numbers of neutrons and masses but same number of protons
Atomic structure
Numbers of protons, neutrons and electrons for atoms and ions given the Ar, mass number and ionic charge
Proton relative mass, charge and location
Relative mass=1
Relative charge=1+
Location= nucleus
Neutron relative mass, charge and location
Relative mass= 1
Relative charge= 0
Location=nucleus
Electron relative mass, charge and location
Relative mass=1/1836( negligible)
Relative charge=1-
Location =in the atoms energy levels
Relative isotopic mass
Mass of an isotope compared with 1/12Th of the mass of an atom of carbon -12
Relative atomic mass
The weighted mean mass of an atom compared with 1/12Th the mass of carbon-12
How is carbon-12 the standard for atomic masses
Strong forces mean protons neutrons and electrons can’t be see, so 12U is used, 1U =proton/neutron mass approx
carbon is used because of its high abudance in nature and ability to measure it
Steps of mass spectrometry
- Sample placed in mass spectrometer
- Sample vaporised + ionised -> positive ions
- Acceleration -> heavy= slow=harder deflections=ions separated
- Detection on a mass spectrum as mass- charge(m/z)= mass/charge,
higher abundance = (mass spectrometry)
larger signal
why does relative isotopic mass have no units
it is a ratio
current accepted model of electron
Rutherford scattering
small dense nucleus surrounded by orbiting electrons
max no of shells=
2n^2
daltons atomic theory
atoms are indivisible particles made of elements that are the same in an element but differ from other elemental atoms
thompson electron discovery
electrons have a negative charge and have a small mass
they can be deflected by magnetic and electric fields
plum pudding model
negative electrons moving in a sea of positive charge
rutherfords proposal after gold leaf experiment
most of mass and positive charge in atoms nucleus
electrons orbit nucleus
balance between positive and negative charges
space between electron and nucleus= most of cells volume
current accepted model
protons and neutrons in nucleus
electrons orbit nucleus in shells
mass in the nucleus
nucleus is tiny compared to atom size
atom is mostly empty space
atomic number of atom represented by letter
Z
mass number represented by letter
A
metals usually - electrons
lose
4 elements that dont usually form ions and why
beryllium, carbon, boron , silicon
requires a lot of energy to transfer outer electrons/ ionisation energy
