Chapter 2 - Atoms, ions and compounds Flashcards
What are the three subatomic particles?
Proton
Electron
Neutron
Where are electrons found?
In orbitals
Charge of electrons
-1
Mass of electron
1/2000
Charge of neutron
0
Mass of neutron
1
Charge of proton
+1
Mass of proton
1
What does the mass number show?
Mass of the nucleus
What does the atomic number show?
Number of electrons or protons
What is an ion?
An element with a different number of electrons
What are isotopes?
Atoms with a different number of neutrons
Why can isotopes change the physical properties of an atom?
Properties can depend on the mass of the atom
What is the relative atomic mass of an atom?
The weighted mean mass compared to 1/12th of the mass of an atom of Carbon-12
What is the relative isotopic mass?
The mass of an atom of an isotope compared with 1/12th of the mass of an atom of Carbon 12
How to work out Ar from isotopic abundance?
1) Multiply the relative isotopic mass by its % abundance
2) Add up all the results
3) Divide by 100
How are the isotopes in a sample calculated?
Using a mass spectrometer
How does a mass spectrometer work?
1) A vaporised sample is ionised to form positive ions
2) The ions are accelerated
3) Heavy ions move more slowly than light ones so they are separated
4) The different speeds are detected on the spectrum and this can be used to determine the amount of each isotope in the sample
How to work out atomic mass using spectronomy
Multiply the relative mass of each isotope by its abundance
Add the results
Divide by the sum of the total isotopic abundances
What is important to remember about the reactive properties of isotopes?
They will stay the same
What are cations?
Positive ions (they have lost electrons)
What are anions?
Negative ions (they have gained electrons)
How is an atom held together?
Some of the mass is used
What is a binary compound?
It contains two elements only
How do you name binary compounds?
Use the name of the metallic element and then change the name of the non-metallic element to have the suffix ‘ide’
What are polyatomic ions?
They consist of multiple elements
Formula for ammonium ion
NH4+
Formula for hydroxide ion
OH-
Formula for nitrate ion
NO3-
Formula for sulfate ion
SO4 2-
Formula for carbonate ion
CO3 2-
What are the two molecules that exist as molecules bigger than diatomic molecules?
P4 and S8
What is a mole?
The mass of a substance that has as many particles as there are atoms in 12g of carbon-12
