Atomic structure and Amount of substance

Why is ionisation energy endothermic?

Energy is required to overcome the electrostatic attraction between the positive nucleus and negative electrons

Why is Lithium, for example, in the S block?

Its highest energy electron is in an S orbital

Sulfuric acid

H²SO⁴

Why does removing an electron from a new shell require alot more energy?

s a new shell would be closer to the nucleus, so the nuclear attraction would be much greater

What does a large ionisation energy change represent?

A change of shell

Why do successive ionisation energies increase?

as electrons are being removed from an increasingly positive ion, so the electrostatic attraction between the nucleus and electrons increase,

What is the general trend of successive ionisation energies?

They increase

How many electrons are lost in every ionisation, per specie?

1

What does Nth ionisation energy refer to?

The charge of the ions being made

What does sulfur having a lower first ionisation energy than phosphorus provide evidence for

Orbital electron pairing

why does sulfur have a lower first ionisation energy than phosphorus?

because its outermost shell contains a paired set of electrons in one of its 3p orbitals, whereas phosphorus has a three unpaired electrons in its outermost orbital. The two electrons sharing the same orbital in sulfur experience electrostatic repulsion, which makes the outermost electron significantly easier to remove despite Sulfur having a greater nuclear charge due to its extra electron

What does aluminium having a greater first ionisation energy than magnesium provide evidence for?

The existence of subshells

Why does Aluminium have a lower first ionisation energy than magnesium, despite being further along the 3rd period?

because its outermost electron is located in a higher-energy 3p sub-shell, which sits slightly further from the nucleus than magnesium’s outer electron in the 3s sub-shell. This 3p electron also experiences additional shielding provided by the inner 3s² electrons

Nitric acid

HNO³

What is the general trend of the first ionisation energy as you go down a group?

First ionisation energy decreases

Why does the first ionisation energy increases as you go across a period?

Outermost electrons are in the same shell, so the distance and shielding remain constant. But there are more protons in the nucleus, so the nuclear charge increases

Why does the first ionisation energy decrease as you go down a group?

More shells, so more shielding and a greater distance from the nucleus, which far outweighs the additional nuclear charge from the additional protons in the nucleus

What is the general trend for first ionisation energy across a period?

The first ionisation energy increases

How does distance from the nucleus affect ionisation energy?

Weaker force of attraction on the outermost electron

Hydrochloric acid

HCL

Hydrogen

H²

Nitrogen

N²

Phosphoric acid

H³PO⁴

Ammonium

NH⁴ (+)

Oxide ion

O (-2)

Sulfide ion

S (-2)

Nitrate ion

NO³ (-)

Sulfate ion

SO⁴ (-2)

Carbonate ion

CO³ (-2)

Hydrogencarbonate ion

HCO³ (-)

Hydride ion

H (-)

Phosphate ion

PO⁴ (-3)

Nitride ion

N (-3)

Oxygen

O²

Fluorine

F²

Chlorine

Cl²

Bromine

Br²

Iodine

I²

Phosphorus

P⁴

Sulfur

S⁸

Diamond

C

Graphite

C

Graphine

C

Relative mass of a proton

1

Relative charge of a proton

+1

Relative mass of a neutron

1

Relative charge of a neutron

0

Relative mass of an electron

1/1840

Relative charge of an electron

-1

what did Dalton say about atoms?

Solid, indivsible spheres of different sizes

What did Thomson suggest in 1897?

Plum pudding model

what was the plum pudding model?

Ball of positive charge with negative electrons embedded in it

Conclusion of alpha scattering experiment

Atom is mostly empty space, with the mass concentrated in the positively charged nucleus

who came up with the nuclear model in 1911?

Rutherford

Who came up with the planetary model in 1913?

Bohr

what was the planetary model?

Electrons orbited the nucleus in fixed, stable energy shells

Who discovered the electron in 1933?

Chadwick

what is the order of the discovery of the subatomic particles?

Electron, proton, Neutron

what is an isotope?

atoms with the same number of protons and Electrons, but a different number of neutrons. Therefore it has a different mass number.

stage 1 of Mass spectrometry

Ionisation

Stage 2 of mass spectrometry

acceleration

Stage 3 of mass spectrometry

flight tube

stage 4 of mass spectrometry

Detection

Describe electron impact ionisation

The firing of high energy electrons from an electron gun to knock one or more electrons off the molecules in the vapourised sample.

Describe electrospray ionisation

The sample is dissolved in a volatile solvent and is injected through a hypodermic needle to give a fine mist. The tip of the needle is attached to the positive terminal of a high voltage power supply. The particles gain a proton.

why isnt Electron impact used for high Mr substances?

it causes fragmentation

describe acceleration in mass spectrometry

The positive ions are accelerated using attraction to a negatively charged metal plate, so that they all have the same kinetic energy

Which ions travel the fastest in the flight tube?

The lightest

how is the proportion of the number of ions hitting the plate at a given time measured?

The size of the current produced

Why is a current created when the positive ions are discharged?

There is movement of electrons

What creates a mass spectrum?

A computer

what causes peaks at lower Mr using electron impact?

Fragmentation

what does a mass spectrum show?

the mass to charge ratio and the abundance of each ion that reaches the detector

Why does the mass increase by 1 when using electrospray ionisation?

A proton is gained

Why may there be a small +1 mass peak?

Heavier isotopes of carbon or Hydrogen

What is the relative atmoic mass of an atom?

The average mass of an element divided by 1 twelth of the mass of a carbon 12 atom.

what is The relative molecular mass?

the average mass of 1 molecules of an element/compound divided by 1 twelth of the mass of a carbon 12 atom.

How many molecules are there in a mole?

6.022x10²³

What is the unit for concentration?

moldm-³

What is the ideal gas equation?

pv=nRT

Unit for pressure

pa

Unit for volume

m³

unit for temperature

K

The molar gas constant

8.31 J

How to convert celsius to kelvin?

C+273

How to convert cm cubed to m cubed?

÷1000000

what is the empirical formula?

the simplest whole number ratio of atoms of each element in a compound.

what is the molecular formula?

the actual number of atoms of each element in a compound.

Define orbital

region of space where there is a 95% probability of finding an electron

What does isoelectronic mean?

Same electronic structure

How does electron shielding affect ionisation energy?

More shells results in a greater shielding of the nuclear charge, so the electrostatic attraction on the outermost electron is reduced

How does nuclear charge affect ionisation energy?

greater nuclear charge, this causes a stronger electrostatic attraction on the outermost electron

What 3 factors affect first ionisation energy?

Nuclear charge, electron shielding, distance from nucleus

General equation of first ionisation energy

X(g)= X+ (g) +e-

Define first ionisation energy

First ionisation energy-the energy required to remove 1 electron from each atom of 1 mole of gaseous atoms

Where is the F block?

Below the transition metals

Where is the P block

from group 3 onwards, excluding helium

Where is the D block?

Between group 2 and group 3

What spin do 2 electrons in 1 orbital have?

opposite

How many electrons can 1 orbital have?

2