1:1 Atomic structure

Sate how the detector enables the relative abundance of each ion to be determined

Relative abundance is proportional to the size of the current

Relative atomic mass

Mean mass of 1 atom of an element / 1/12th of the mass of one atom of 12C (carbon-12)

TOF equations

KE = ½ mv²

KE in J, M of an ion in Kg, V in ms^-1

Mass of an ion in Kg = atomic mass number of ion / avogadros number

The divide by 1000 to take answer from grams to Kg

T=D * square root (M/2KE) Remember as DM ME

D=T * square root (2KE/M)

How to identify elements from successive ionisation energies

Looking for large jump after the nth electron is removed as the n+1th electron is removed from an orbital lower in energy / closer to the nucleus / different shell

Meaning of electron impact ionisation

High energy electrons from an electron gun are used to knock out an electron from each molecule or atom

Molecule loses and electron forming M+

Electrospray ionisation

Sample is dissolved in a volatile solvent

Injected through a needle at a high voltage and that is positively charged

Each molecule gains a proton / H+

What kind of ion travels slowest in flight tube and reaches the detector last

Ion that has the highest mass to charge ratio so will travel the slowest

How are ions detected at the detector

Ions hit a detector ad each ion gains an electron, generating a current

What is the mass number of an atom

Number of protons and neutrons in the nucleus of an atom

Why is necessary to ionise the isotopes of chromium before they an be analysed in a TOF mass spectrometer

Ions will interact with and be accelerated by a electric field

Ions create a current when hitting the detector

General Trend in 1st IE across period 2 and the deviations from general trend

General trend is that the 1st IE increases as there are more protons, electrons are in the same energy level and there is no extra shielding. There is a stronger attraction between nucleus and outer electron

Deviation between Be→B : B has a Lowe 1st IE than Be as its outer electron is in 2p and this is higher in energy than 2s, so more easily removed

Deviation N→O : O is lower than N as there is 2 electron in 2p that need to pair. O experiences electron repulsion, so its easier to remove electron from O

Isotopes definition:

Do the chemical properties of isotopes differ?

Atoms of the same element with the same number of protons but a different number of

No difference in chemical properties, because they all have the same electronic configuration and the same number of outer electrons

Explain why the ionisation energy of every element is endothermic

Heat or energy needed to overcome the attraction between the negative electron and the positive nucleus or protons

Definition of first ionisation energy

Energy / enthalpy needed to remove one mol of electrons from one mole of atoms in a gaseous state

When writing electron configurations, where must the title numbers go

At the top, like to the power of:

1s² 2s²

Definition of electronegativity

Ability of an atom to attract a shared pair of electrons towards itself in a covalent bond

What can be adjusted in the mass spectrometer to enable ions formed by the different spotted to be directed onto the detector

Electromagnet

What is used to ensure the relative abundance of isotopes

Mass spectrometer

Definition of a catalyst

A substance that speeds up the rate of a reaction and is chemically unchanged at the end of a reaction

Why might the value calculated of relative atomic mass be different from the relative atomic mass given in periodic table

The Ar in periodic table takes into account of the other isotopes

Describe acceleration and ion drift

Acceleration - the positively charged ions are accelerated by an electric field so they all have the same kinetic energy

Ion drift - the ions enter a region with no electric field, so they just drift through it. Lighter ions will drift faster than heavier ones