Atomic Structure and Isotopes Flashcards
What was stated in Daltons atomic theory
Atoms are tiny particles made of elements
Atoms cannot be divided
All the atoms in an element are the same
Atoms of one element are different to those of other elements
What did Thompson discover about electrons
They have a negative charge
they can be deflected by a magnet and electric field
They have a small mass
Explain the plum pudding model
Atoms are made up of negative electrons moving around in a sea of positive charge
What were Rutherfords proposal after the gold leaf experiment
Most of the mass and positive charge of the atom are in the nucleus
Electrons orbit the nucleus
Most of the atoms volume is the space between the nucleus and the electrons
Overall positive and negative charges must balance
Explain the current model of the atom
Protons and neutrons are found in the nucleus
Electrons orbit in shells
Nucleus is tiny compared to the total volume of atom
Most of Atoms mass is in the nucleus
Most of the atom is empty space
Which letter is used to represent the atomic number of an atom
Z
which letter represents the mass number
A
Define isotope
Atoms of the same lement that have the same proton number but different number of electrons
Why does different isotopes of the same element react in the same ways
Neutrons have no impact on the chemical reactivity
Reactions involve the electrons, isotopes have the same number of electrons in the same arrangement
Define relative atomic mass
The weighted mean mass of an atom of an element compared with 1/12 of the mass of an atom of carbon 12
Define relative isotopic mass
The mass of an atom of an isotope compared with 1/12 of the mass of an atom of carbon 12
What two assumptions are made when calculating mass number
Contribution of the electron is neglected
Mass of the proton and neutron is taken as 1.0 u
What are the uses of mass spectrometry
Identify unknown compounds
Find relative abundance of each isotopes of an element
Determine structural information
How does a mass spectrometer work
The sample is made into positive ions
They pass through the apparatus and are separated according to mass to charge ratio
A computer analyses the data and produces mass spectrum
What are molecular ions
Covalently bonded atoms that lose or gain electrons
