Unit 1 - Organic Chemistry Flashcards by Jenny Hartmann

What is electromagnic radiaton

Form of radiation released by an electomagnetic process

-physical interaction between charged particles

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What happens when charged particles are accelerate

They produce electromagnetic waves

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The longer/shorter the wavelength, the greater the energy of the wave

Shorter

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What is the electromagnetic spectrum

Range of all possible frequencies in electromagnetic radiation

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What does rlectromagnetic radiation include

Light
Xray
Radio waves

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Violet = (1) wavelength
Red = (2) wavelength

1 longest

2 shortest

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Define wavelength

Distance between adjacent crest of wave

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What is the adjacent crest of the wave

Highest point

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Define frequency

Number of wavelengths that pass a fixed point in time unit

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Define valency

Speed of light (constant of 3x10^8)

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What is wave particle duality

Electromagnetic radiation can be considered both, waves and particles

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What is a quanta

Can transfer a specific amount of Energy

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What information can light provide about an atom

Quantity and type

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What is an atomic spectra

Caused by electroms moving between different E levels

=fixed for one atom

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Quantum theory

Matter can only emit/ absorb E in small fixed amount

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When an electron absorbs a photon of E it moves from lower/higher E level to a lower/higher level

Lower

Higher

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How is light emitted

When the electron that has been promoted to a higher E level drops back down

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What is evidence for the existence of Energy levels

The light E emitted by an atom produces a spectrum that is made up of a series of lines descrete (quantised) E levels

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Photons of high/low radiation can transfer greater amounts of energy

High

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Radiation is absorben when electrons are promoted to a lower/higher level

Higher

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What is an absorption spectrum

Produced by measuring how the intensity of absorbed light varies with wavelength

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Why are high temperatures used in emission spectroscopy

To excite electrons within atoms

When e- drops= quantum emitted

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What is an emission spectrum

Produced by measuring the intensity of light emitted or absorbed

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What is the concentration of an element related to in atomic spectroscopy

Intensity of emitted or absorbed light

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What is referred to as ground state

Lowest possible electronic configuration the electrons in an atom can adopt

Levels become closer/further apart as n increases

Closer

What is rhe convergence limit

Point at which E levels become so close together that they converge

State the Aufbau Principle

Orbitals are filled in order of increasing energy

State the Pauli Exclusion Principle

No 2 electrons in one atom can have the same set of 4 quantum numbers - no orbital can hold more than 2 electrons - electrons have opposite spin

State Hunds Rule

When degenerate orbitals are available, electrons fill each singly, keeping spins parallel before pairing starts

Why does 4s get filled up before 3d

Because it has a lower energy state

Whats an isolated atom

Exists separately without any bonding | -orbitals in each subshell are degenerate

Whats ionisation energy

Energy required to remove one mole of electron from one mole of gaseous atom

Full shell = (1) = high/low IE | half full shell = (2) = high/low IE

1 very stable, high | 2 stable, high

Why is IE higher for stable molecules

More difficult to remove electron

How are covalent bonds formed

Formed when aromic orbitals overlap to form molecular orbital

What are molecular orbitals

Overlapping atomic orbitals | -form covalent bonds

Whats VSEPR

valency shell electron pair repulsion Theory that pairs of e- that surround central atom of a molecule or ion are arranged as far apart as possible to minimise electron repulsion

What can vsepr be used for

Can be used to predict shapes of molecules and polyatomic ions

What must be considered for vsepr

Bonding and non bonding pairs

Whats a dative bond

Both electrons come from one of the elements involved in bond -covalent

Why do bonding e- repell less than non nonding e-

Because they are attracted by 2 nuclei

Transition metals have at least one ion with (1)

And incomplete subshell

Are 4s filled before or after 3d for transition metals

Before

High oxidation number= 1 | Low oxidation number= 2

1 oxidation | 2 reduction

Compounds with high oxidation states 1 | Compounds with low oxidation state 2

1 oxidising agend | 2 reducing agend

What di transition metal complexes consist of

Central metal ion surrounded by ligands

What are ligands

Molecules/ neg ions that donate electron pairs into unfilled d orbitals

Whats monodentate

Donates 1 e- pair eg water

Whats bidentate

Donates 2 e- pairs eg oxalate

Whats hexadentate

Donates 6 e- pairs eg EDTA4-

What does colour depend on in transition metals

Oxidation state

Properties of ligands (3)

Have at least one lone pair | Usually neg/molecule

What is coordination number

Total number of binds from ligand to central mental

What is the shape of an ion complex determined by

Coordination number

What dies colour of transition metals depend on

Oxidation state Identity Ligands attached

Some of visible spectrum absorbed=

Colourr

Non of visible spectrum absorbed

Colourless

All of visible spectrum absorbed

Black

How are transition metal complexes able to absorb light

Because of 5 degenerate d orbitals splitting in terms of energy

What properites does energy have in free transition metal ions

Degenerate

What are ftee transition metal ions

Transition metals with no ligands

What is the spectrochemical series

A list of ligands according to how strongly they split d orbitals in transition metal complexes

Spectrochemical series from strongest to weakest

CN->NH3>H2O>OH->F->Cl->Br->I-

What is crystal field strength

Difference in energy between two subshells of d orbitals

When one colour is absorbed, what colour is emitted

Complementary colour eg green/purple

How do d orbitals split in higher/lower energies

E- present in approaching ligands cause e- in orbutals lying along axes to be repelled

When is light emitted

When e- jump from higher to lower energy level

When is light absorbed

When e- from lower energy level are promoted to higher

What are strong field ligands

More likely to occur in UV region

What are heterogenous catalysts

In different state to reactant

What are homogenous catalysts

Same state as reactant

How can heterogenous catalysts be explained

Formation of activated complexes and absorption of reactive molecules into active site Presence of unpaired e- or unfilled d orbitals allow complexes to form

How can homogenous catalysts be explained

Changing oxidation states cause formation of complexes

Unit 1 - Organic Chemistry Flashcards

(74 cards)