EL

Ammonium ion

nH4+

Number of moles

Mass/Mr

Number of moles (gas)

(Pressure x volume) / (gas constant x Temperature)

Number of moles (conc)

Concentration x volume

Atomic number

The number of protons in the nucleus of an atom

Composition by mass

Relative mass of each element in a compound

Emperical formula

The simplest whole number ratio of atoms to each element present in a compound

Fusion reactions

Lighter nuclei join to give heavier nuclei, under high temperature and pressure

Ion

Particle formed when an atom loses or gains electrons, giving an overall charge

Ionic compound

Compound made up of oppositely charged ions, held together by electrostatic forces

Isotopes

Atoms of the same element, with the same number of protons, but different number of neutrons

p orbital

Dumbbell shaped electron orbital, who's subshell can hold 6 electrons

Percentage yield

actual yield/theoretical yield x 100

s orbital

spherical orbital which can hold up to 2 electrons

Standard solution

a solution of known concentration

subshell

A subdivision of an energy level in an atom. They are divided into orbitals.

Covalent bond

Strong electrostatic attraction between two nuclei and the shared pair of electrons between them

Dative covalent bonding

When one atom donates both electrons

Electron pair repulsion

the repulsion between pairs of electrons, meaning the shape of a molecule adopts a position where pairs of electrons are as far from each other as possible

Giant atomic structure

Large structure containing lots of covalent bonded atoms

Giant ionic lattice

Regular repeated structure of oppositely charged ions

Ionic bond

Strong electrostatic attraction between two oppositely charged ions

Metallic bond

Strong electrostatic attraction between positive metal ions and the sea of delocalised electrons that surround them

Anion

Negatively charged ion

Cation

Positively charged ion

Charge density

Ratio of charge to volume of an ion

First ionisation energy

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

precipitation reaction

Reaction in which solutions react to form an insoluble product

Alkali

A base which is soluble in water

Neutralisation

Reaction between acid and base which react together to form water and salt

Ionic equation- Neutralisation

H+ (aq) + OH- (aq) -> H2O (l)

strong acids and bases

dissociate completely in water

weak acids and bases

Dissociate partially in water

Absorption spectra

Spectrum of frequencies of electromagnetic radiation, which has been transmitted through a molecule

Emission spectra

Spectrum of frequencies of electromagnetic radiation that has been emitted by an atom undergoing a transition from a state with higher energy to lower energy

mass spectrometry

Technique used to identify compounds and determine their relative abundance and mass

isotopes of hydrogen

Hydrogen (1 neutron)

Deuterium (2 protons)

Tritium (3 protons)

Avogadro's constant

6.02 x 10^23

The number of particles per mole

Water of crystallisation

Water molecules that are bonded into a crystalline structure of a compound

percentage composition

Mr of element/Mr of compound x 100

Making up standard solution

1. Weigh boat with solid

2. Add solid to beaker

3. Reweigh boat

4. Record mass difference

5. Add DI water to beaker then dissolve

6. Transfer to volumetric flask, with washings

7. Make up to 250cm^3 then invert

Titration Method

1. Fill burette with unknown solution

2. Use pipette + pipette filler and add 25cm^3 of standard solution to conical flask

3. Add indicator

4. Titrate until colour change, recording amount of unknown substance added

5. Repeat until two concordant results (within 0.1cm^3 of eachother)

How many electrons does the s-subshell hold?

2

How many electrons does the p-subshell hold?

6

How many electrons does the d-subshell hold?

10

S-orbital shape

Spherical

P-orbital shape

Dumbbell

Fusion Reaction

Two lighter nuclei join to give a single heavier nucleus, releasing energy

Ionic Bonding

• Metal + Non-metal

• Conduct electricity when molten/aqueous

• When electrons are transferred, they form ions, which attract through electrostatic forces, forming giant ionic lattice

Covalent Bonding

Two non-metals

Dative Covalent Bond

Both electrons in a shared pair come from a single atom

Simple Covalent Bond

• Held together by intermolecular forces

• Shape of molecule is determined by number of bonding/lone pairs

• Electron pairs repel to have largest angle possible between bonds

Diamond

Carbon atom joined to 4 other carbon atoms

Graphite

• Carbon atom joined to 3 other carbon atoms
  

• One delocalised electron per carbon, which moves freely- Conducts electricity
  

• Flat hexagonal sheets -Intermolecular forces between layers are weak, meaning layers slide over each other

• Can act as lubricant

Metallic Bonding

• Two metals

• Giant lattice of positive atoms surrounded by sea of delocalised electrons

• Strong electrostatic forces of attraction between oppositely charged particles

• Malleable due to uniform layers

• Good conductors

• High mp

Melting point across period 2

Peaks in middle due to type of bonding

Melting point across period 3

Peaks in middle due to type of bonding

Nitrate

NO3-

Sulfate

SO4 2-

Carbonate

CO3 2-

Hydroxide

OH-

Ammonium

NH4+

Bicarbonate

HCO3-

Copper

Cu2+

Zinc

Zn2+

Lead

Pb2+

Iron (II)

Fe2+

Iron (III)

Fe3+

Group 2 Metals + water

• X + 2H2O -> X(OH)2 + H2
  

• Forms alkaline solution

Group 2 Metals + Water (+steam)

• X + H2O -> XO + H2
  

• Faster

Group 2 reactivity with water

Increases down group

Alkalinity of group 2 metals

Increases down group

Group 2 metals + oxygen

2X + O2 -> 2XO

Thermal Decomposition of Group 2 Carbonates

XCO3 -> XO + CO2

Become more stable to heat down group

Solubility of Group 2 Carbonates

Decreases down group

Solubility of Group 2 Hydroxides

Increases down group

First Ionisation Energy

The minimum energy required to remove one mole of electrons from one mole of atoms in a gaseous state (KJ/mol)

X(g) -> X(g) + e-

Trend of ionisation energy across period

Increases due to decreasing atomic radius and greater electrostatic forces of attraction

Trend of ionisation energy down group

Decreases down group due to increasing atomic radius and electron shielding

What does a large jump between successive ionisation energy mean?

The electrons are being removed from a new shell

Ionic Equation for Neutralisation

H+ + OH- -> H2O

Basicity Trend of Group 2 oxides

Basicity increases down group

Basicity Trend down Group 2 hydorxides

Increases down group

Group 2 Hydroxides + Dilute Acids

Type of neutralisation
X(OH)2 + 2HCl -> XCl2 + 2H2O

Salts formed from nitric acid

Nitrate salts

Salts formed from hydrochloric acid

Chloride salts

Salts formed from sulfuric acid

Sulfate salts

Energy of Light (Equation)

Energy of Light = Planck's Constant x Frequency of light

Speed of Light (Equation)

Speed of Light = Wavelength x Frequency of light

Electromagnetic Spectrum
Raging Martians Invaded Venus Using X-ray Guns

(Highest to lowest energy)

Radio

Microwave

Infrared

Visible

Ultraviolet

X-ray

Gamma

Emission Spectrum

Atoms absorb EM radiation, promoting electrons to higher energy levels

As electrons fall back to ground state, they release EM radiation

Light emitted has different wavelengths, called emission spectrum

Absorption Spectrum

Photon with an energy the same as the gap between two energy levels hits a gap, the electron in the lower energy level absorbs energy and is promoted to higher energy level. Photon won't be absorbed if energy does not correspond to difference in energy levels

How to obtain emission spectra

White light is shined on material as it contains all wavelengths of visible light

Gaps in the absorption spectra corresponds to energies for which there is a difference in energy levels for the element. Gaps when wavelengths have been absorbed

Relationship between absorption and emission spectrum

Absorption spectrum is exact inverse of emission spectrum

Similarities of absorption and emission spectra

Both line spectra

Lines in same position for given element

Lines become closer at higher frequencies

Lines represent transitions to or from particular energy level

Differences between emission and absorption spectrum

Emission spectrum consists of coloured lines on black background
Absorption spectrum consists of black lines on coloured background

Flame test process

1. Clean nichrome wire using conc. HCl

2. Dip wire into solid sample of compound

3. Insert loop into blue flame of bunsen burner

4. Record colour of flame

Li+ Flame test

crimson

Na+ flame test

yellow