Topic 1-Atomic Structure And Periodic Table And Periodicity

The weighted mean mass of an atom of an element compared to 1/12th the mass of a carbon-12 atom

The mass of an atom of an isotope compared to 1/12th of the mass of a carbon 12 atom.

The mass spectrometer is a machine which provides chemists with a way to measure and compare masses of atoms and molecules

Vaporisation-heat up molecules so sample turns into gas so individual atoms are separated Ionisation-An electron gun is used to knock off 1 electron via a collision causing a positive ion to be formed Acceleration-The positive ions will move towards the negative charged detector Deflection-A magnetic field deflects the beam of ions e.g. heavier ions will deflect less but lighter will move more Detection-Ions will detected

To prevent ions from colliding with molecules in the air

The energy required to remove 1 mole of electrons from 1 mole of gaseous atoms to form 1+ ions

When an electron moves up an electron shell When an electron moves down an electron shell

Energy required to remove 1 mole of electrons from 1 mole of gaseous 1+charge to form 2+ ions

Determination of RAM of an element Detection of drugs and their metabolites in urine In the pharmaceutical industry

Region of space outside an atoms nucleus where there there is a high probability of finding an electron with opposite spins

The s block comprises the elements in groups 1 and 2 The outermost electron is in an S orbital

Elements in group 3,4,5,6,7,8 Last electron is a p orbital

The 4s orbital fills below the 3d orbital because it has lower energy

Aufbau principle-electrons go into the orbital with the lowest available energy Each orbital can only contain 2 electrons with different spins When there are 2 or more orbitals at the same energy, they fill singly before electrons pair up

Electron to electron repulsion,repulsion increases energy of the electrons above value they would have had This decreases nucleur charge

Net charge on a nucleus,after allowing for the shielding effect of inner electrons

It does stay the same as increase in proton number(which increases attraction and charge) is outweighed by an increase in electron shielding

Radius-greater radius means less ionisation energy as attraction is weaker Sublevel-an electron from a full or half sublevel requires more energy Shielding-greater shielding means more ionisation energy Nucleur charge-amount of protons Orbital in which they exist

An ion will lose its outer shell so has fewer electrons and shells This decreases electron repulsion(shielding) so ENC increases Increases attractiveness of electrons to nucleus

The atom would have gained one or more electrons so repulsion between them increases,attraction between nucleus and electrons decrease so shells move further away increasing atomic radius

Amount of energy requires to remove an electron from an isolated atom

After the first ionisation energy,positive ions will not want to lose another electron so attractive forces are stronger due to less shielding causing more energy required to break the bonds More electrons being removed decreases atomic radius which increases attraction so more energy required to remove

As you go down from one atom to the next,number of protons increase by 1 so ENC increases but so does the no of 3D electrons The 3D electrons are most stable half full or fully full so this causes screening The extra proton and screening cancel out

Atomic number increases,the positive charge of nucleus increases do ENC increases Ionisation energies increase as you go across a period Ionisation energies decrease down a group