Atomic Structure Flashcards
What are the characteristics of a proton ?
Located in the nucleus , relative mass of 1 and charge of +1
What are the characteristics of a neutron?
Located in the nucleus , relative mass of 1 and charge of 0
What are the characteristics of a electron?
Located outside the nucleus , with a mass of 1/1840 and charge of -1
What is the arrangement of sub atomic particles ?
The protons and neutrons are held together by a strong nuclear force ,which are stronger than the electrostatic forces of attraction which over comes the repulsions between p+n
What does the symbol of A stand for
The mass number of protons plus neutrons in the nucleus
What does the Z symbol stand for
The atomic number , the number of protons in the nucleus , the number of electrons are the same as number of protons
What are ions
By gaining or losing electrons , they have a sign next to them
What are isotopes and properties
Atoms with the same number of protons but different amount of neutrons, different isotopes of the same element have same chemical properties but different physical
What is relative atomic mass
The average mass of the atom of an element on a scale where carbon-12 is exactly 12.
What is mass spectrometer
Used to analyse compounds, and can find illegal substances
How does a mass spectrometer work
- under a high vacuum to prevent ions colliding with air particles
- the sample is ionised by it being dissolved in a polar substance,and pushed through a needle ,and a high voltage is applied causing electron to be lost leaving positive ions
- the + ions are accelerated by the field giving all same Ke,lower mass/charge ration cause greater acceleration
- ions drift through region of no electric field
- ions are detected and times noted of how long they took and ions create a current as they hit
How do you interpret a mass spectrum
If a sample is a element each line is a different isotope , the height of the peak gives the relative isotopic abundance
How do you calculate relative atomic mass from from a spectrum
- for each peak read the %abundance on the yaxis and the mass on the x and multiply them
- add them up
- divide by 100
What is the formula to work out number of electrons
2n^2
How many electrons can orbitals have
S-2
P-6
D-10
How does arrows in boxes show electronic configuration
Each box represents one orbital , each arrow represents one electron .up and down arrows represent arrows spinning in different directions
What are the rules for allocating electrons in boxes
- Lower energy ones are filled first
- fill singly before pairing
- no orbital can hold more than 2
How do you write electronic structure
1s2 2s2 2p6 3s1 sodium
What is the first ionisation energy
The energy required to remove 1 electron from 1 mole of gaseous atoms to form 1 mole of gaseous ions
What is equation for the first ionisation
Element->element +e-
What effects ionisation energy
Nuclear charge -more protons stronger attraction
Distance from nucleus- close is more attrative
Shielding -more shells more electrons
What is the definition of second ionisation energy and equation
Energy required to remove an electron from each ion in 1 mole of gaseous 1+ions
:element->element^2+ +e-
What is the general equation for successive ionisation energies
X(n-1)->X^n+ +e-
What is the trend in ionisation energies going down group 2
Ionisation energies decrease down due to the shielding and the electron further away from nucleus
What is the ionisation trend across periods
Ionisation energies increase across as harder to remove outer e-
Why are ions used in mass spec
Ions are detected at detector
Ions are accelerated
How do u calculate relative abundance
100
