C3- Atomic Structure Flashcards
Tell me what John dalton said about atoms
All matter is made of atoms
Atoms are tiny hard spheres that can’t be broken down into smaller parts
Can’t be created or destroyed
The atoms in an element are all identical buy each element has its own type of atom
Tell me the 3 subatomic particles
Protons
Electrons
Neutrons
How are the masses and charged made/ what are they based on
They are relative masses and relative charged compared to s protons
Eg a proton had a mass of one - so anything that has the same mass must also be one
What is a proton like
It has a positive +1 charge and a relative Mass of 1
Tell me about electrons
It has a negative -1 charge and a 1/1835 mass (negligible)
Tell me about neutrons
Have a neutral charge 0 and a mass of 1
What’s in the centre of an atom
A nucleus containing protons and neutrons
What’s the nucleus of an atom surrounded by
Electrons arranged in electron shells at different distances from the nucleus
What are the atoms in an element like
Always have equal numbers of protons and electrons and so have no overall charge
What is most of an atom
Empty space
How is the modern day atom and atom according to John Dalton in 1805 different
We now have discovered there are subatomic particles - not just tiny spheres
Where is most of a mass of an atom
The nucleus
How do we know mosh of an atom is empty space
Rutherford did an experiment were he fired positive particles through thin gold foil and most passed through - he explained this by suggesting most of atoms were Empty space
How were elements originally ordered
Placed in order of masses of the atoms
This was a problem as it caused some elements to be grouped with others that had very different properties - so some were swapped
How is the periodic table grouped now
By the number of protons in their atoms THE ATOMIC NUMBER
What is the mass number
The total number of protons and neutrons
How is a symbol written on periodic table
The symbol of element with the mass number above it and atomic number below it
What’s an isotope
The same element with different masses - the atoms are known as isotopes
They have the same atomic number but different mass number
Will chemicals react the same way
How do we refer to an isotope
By adding its mass number to the elements name
What’s nuclear fission
Splitting an atom - produces new elements and transfers large amounts of energy
Nuclear power stations use the energy from nuclear fission to produce electricity
What’s the relative mass of an isotope
It’s mass number
How do elements exist with isotopes
All elements are s mix of isotopes
We calculate an elements relative atomic mass (RAM) - the symbol is A(little bottom right corner r)
What’s the relative atomic mass
The mean mass of an atom compared with carbon-12
It takes into account all the isotopes of the element and the amounts of each.
each RAM is not a whole number buy most valued are rounded to a whole number
The RAM of an element and its atomic number are shown on the periodic table
What are abundances
Overall properties
Eg the 2 isotopes of chlorine are 75% of 1 type of isotope and 25% of other
How do we calculate RAM
Total mass of the atoms divided by the total number of atoms
To get the total mass of the atoms multiply its abundance by the mass
