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Elements Of Life Flashcards

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1
Q

Moles =

A

Mass divided by mr

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2
Q

Percentage yield =

A

Experimental yield divided by actual yield. x 100

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3
Q

Concentration =

A

mass or moles divided by volume

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4
Q

Avogadros constant

A

6.02 x 10^23 = 1 mole

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5
Q

1 mole =

A

Atoms in 12g of carbon

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6
Q

Hydrated

A

When water is present

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7
Q

Anhydrous

A

When water is removed

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8
Q

Water is slightly polarised

A

Because the hydrogen has a slightly positive charge and oxygen has a negative charge

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9
Q

Ions are held together

A

By strong electrostatic forced of attraction

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10
Q

Group 2 metals in a carbonate, precipitate intensifies

A

Down the group

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11
Q

Group 2 metals in a hydroxide, precipitate intensifies

A

Up the group

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12
Q

First ionisation enthalpy

A

This is the energy required for an electron to be pulled out of an atom in a gaseous state

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13
Q

Sub shells existence is supported by

A

Ionisation enthalpy

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14
Q

Group 2 has a greater charge density

A

Distorting the carbonate ion more making it easier to separate

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15
Q

Cm3 to dm3

A

Divide by 1000

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16
Q

Speed of light =

A

Wavelength x frequency

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17
Q

Energy =

A

Planck constant x frequency

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18
Q

Acid + metal

A

Salt + hydrogen

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19
Q

Acid + metal oxide

A

Salt + water

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20
Q

Acid + metal hydroxide

A

Salt + water

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21
Q

Acid + metal carbonate

A

Salt + water + carbon dioxide

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22
Q

Abundance of isotopes =

A

(% x Mr) + (% x Mr) all divided by 100

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23
Q

Relative abundance =

A

Relative intensity divided by total relative intensity all x 100

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24
Q

Acid

A

Has a ph less than 7
A compound that dissociates in water to produce H ions
A proton donor

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25
Q

Alkali

A

Has a ph greater than 7

A base that dissolves in water to produce OH ions

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26
Q

Base

A

A compound that reacts with an acid to produce water

A proton acceptor

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27
Q

Charge density

A

This is a measure of the concentration of charge on an ion

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28
Q

Empirical formula

A

The empirical formula tells you the simplest ratio of the different atoms in a compound

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29
Q

Group

A

A vertical column in the periodic table

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30
Q

Molar mass

A

The molar mass of a substance is the mass of 1 mole of it

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31
Q

Mole

A

A mole of a substance is 6.02 x 10^23 particles of it

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32
Q

Molecular formula

A

Tells you the actual numbers of the different atoms in a compound

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33
Q

Neutralisation

A

When an acid reacts with an alkali to form salt + water

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34
Q

Oxonium ion

A

Present in every acidic solution

Formed when a proton is donated to a water molecule and forms H3O ion

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35
Q

pH

A

This indicates how strongly acidic or alkaline a solution is

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36
Q

Polarise

A

The ability of an ion to distort the charge cloud of an oppositely charged ion

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37
Q

Relative atomic mass

A

This is the mass of the formula of a compound relative to an atom of carbon - 12

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38
Q

Thermal decomposition

A

This is the breaking down of a compound using heat

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39
Q

Thermal stability

A

A compound with the greatest thermal stability is the one which needs the highest temperature to decompose it

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40
Q

Water of crystallisation

A

Water molecules fitted in a regular pattern within the crystal lattice of an ionic solid

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41
Q

Absorption spectrum

A

This is produced when electrons move from a lower energy level to a higher one
It looks like a rainbow with black lines on it

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42
Q

Alpha radiation

A

Composed of 2 protons and 2 neutrons

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43
Q

Anion

A

An ion with a negative charge

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44
Q

Atomic number

A

Tells you the benumbed of protons I’m the nucleus

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45
Q

Atomic orbital

A

Sub shells are split into atomic orbitals

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46
Q

Cation

A

An ion with a positive charge

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47
Q

Chromosphere

A

The region outside a stars surface which is made of atoms, ions and molecules

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48
Q

Closed shell arrangements

A

These are typical of noble gases

Their shells and sub-shells are fully occupied by electrons

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49
Q

Covalent bonds

A

These are formed between two non-metal atoms

The electrostatic attraction between both nuclei and the pair of electrons holds the atoms together

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50
Q

Dative covalent bond

A

A covalent bond in which both the shared pair of electrons come from the same atom

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51
Q

Delocalised electrons

A

These are seen in metallic bonding

They do not belong to specific atoms but are shared

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52
Q

Electron configuration

A

This is the arrangement of electrons in shells, sub shells and atomic orbitals

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53
Q

Electrostatic bond

A

It is an attraction between something with a positive charge and something with a negative charge

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54
Q

Emission spectrum

A

This is produced when electrons move from a higher to a lower energy level
It is coloured lines on a black background

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55
Q

Excited

A

An electron is excited if it moves from a lower to a higher energy level

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56
Q

Frequency

A

This is the number of vibrations per second

Units are Hertz (Hz) or s^-1

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57
Q

Planck constant

A

6.6.3 x 10^-34 Js

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58
Q

Fusion

A

The joining of 2 small nuclei to make a larger one
It occurs at a high speed to overcome repulsion between positive nuclei
High temperature and pressure are needed

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59
Q

Giant covalent network structure

A

This is typical of group 4 elements and their compounds
All of the bonds are strong covalent ones
There are no distinct molecules

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60
Q

Giant ionic structure

A

This is typical of ionic compounds

The ions are held in a 3D lattice by ionic bonds

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61
Q

Giant metallic structure

A

This is typical of metals

The metal ions are attracted to the delocalised electrons

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62
Q

Group when used to describe electrons

A

A group can be a single, double or triple bond or a lone pair of electrons

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63
Q

Intermolecular bond

A

Bond between atoms in a molecule

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64
Q

Intramolecular bond

A

Bond between molecules

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65
Q

Relative atomic mass

A

The average mass of an atom of an element on a scale where an atom of carbon 12 is 12

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66
Q

Relative isotopic mass

A

The mass of an atom of an isotope of an element on a scale where an atom of carbon 12 is 12

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67
Q

Relative formula mass (Mr)

A

The average mass of a molecule of formula unit on a scale wearing atom of carbon 12 is 12

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68
Q

To find the Mr

A

Add up The relative atomic mass values of all the atoms in the molecule

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69
Q

Relative atomic mass is an

A

Average of the isotopes so it is not usually a whole number (eg Cl 35.5)

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70
Q

Proton charge

A

+1

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71
Q

Neutron charge

A

0

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72
Q

Electron charge

A

-1

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73
Q

Proton relative mass

A

1

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74
Q

Neutron relative mass

A

1

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75
Q

Electron relative mass

A

1/2000

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76
Q

Mass number

A

The total number of protons and neutrons in the nucleus

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77
Q

Atomic number

A

The number of protons in the nucleus which is also the same as the number of electrons in the nucleus

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78
Q

Negative ions have more

A

Electrons than protons

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79
Q

Positive ions have fewer

A

Electrons than protons

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80
Q

Isotopes are

A

Atoms of the same element with different numbers of neutrons

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81
Q

Isotopes have the same

A

Configuration of electrons so they’ve got the same chemical properties

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82
Q

Isotopes have different

A

Physical properties because physical properties depend more on the mass of an atom

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83
Q

John Dalton

A

Set an atom was a solid sphere and that different spheres made up different elements

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84
Q

JJ Thompson

A

Said the atoms were not solid and came up with the plum pudding model

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85
Q

Plum pudding model

A

Had a positively charged sphere with negative electrons in bedded in it

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86
Q

Rutherford experiment

A

Gold foil experiment and fired alpha particles add a thin sheet of gold most passed straight through and a few deflected so the plum pudding model was wrong

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87
Q

Ernest Rutherford did

A

The gold foil experiment and proved the Plum pudding model was wrong and came up with the nuclear model of an atom

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88
Q

Nuclear model of an atom

A

Small positive charge in the nucleus
Nucleus surrounded by a cloud of negative electrons
Mostly made up of empty space

89
Q

Mosley discovered

A

That the charge of the nucleus increased from one element to another

90
Q

Rutherford discovered

A

That the nucleus contains positively charged particles that he called protons
the charges of the nuclei of different atoms could be explained the atoms of different elements have a different number of protons in the nucleus

91
Q

James Chadwick discovered

A

But there were other particles in the nucleus that had mass but no charge (neutron)

92
Q

Bohr model

A

Electrons can only exist in fixed orbitals or shells not anywhere in between
Each shell has a fixed energy

93
Q

When an electron moves between shells

A

Electromagnetic radiation is admitted or absorbed because the energy of shells is fixed the radiation will have a fixed frequency

94
Q

Noble gases are stable

A

Because they have a full shell of electrons

95
Q

Quantum model

A

You can never know where an electron is or which direction it’s going in at any moment but you can say how likely it is to be at any particular point in the atom (The denser the dots the more likely an electron is to be there)

96
Q

Measured relative masses

A

Use a mass spectrometer

97
Q

Mass spectrometer steps

A

Vaporisation
Ionisation
Acceleration
Detection

98
Q

Vaporisation

A

The sample is turned into a gas using an electrical heater

99
Q

Ionisation

A

The gas particles are bombarded With high energy electrons to ionised them. Electrons are knocked of the particles leaving positive ions

100
Q

Acceleration

A

The positive ions are accelerated by an electric field

101
Q

Detection

A

The time taken for the positive ions to reach the detector is measured this depends on an iron mass and charge (light highly charged ions will reach the detector first while heavy ions with a smaller charge will take longer)
For each sample analysed a mass spectrum is produced

102
Q

A mass spectrum

A

Y axis gives the abundance of the ions whilst the X axis gives the mass overcharge ratio (relative mass)

103
Q

Mass spectrum recognising

A

Isotopes- if the sample is an element each line will represent a different isotope of the element

104
Q

To find the AR using a mass spectrum

A

For each peak read the relative isotopic abundance and times by the relative isotopic mass
At the totals and then divide by 100

105
Q

Percentage relative isotopic abundance =

A

(Relative abundance/ total relative abundance) x 100

106
Q

To find the Mr using a mass spectrometer

A

The peak further to the right shows the Mr

107
Q

Fragmentation pattern

A

Bombarding with electrons make some molecules break into fragments these are shown on a mass spectrum

108
Q

If an atom is unstable

A

It will break down to become stable, the instability Could be caused by having too many neutrons or not enough neutrons or too much energy in the nucleus

109
Q

Breaking down of an unstable atom is called

A

Radioactive decay

110
Q

Alpha particles

A

Like helium I stopped by paper and have a strong ionising ability and slight deflection in electric field

111
Q

Beta particles

A

A fast moving electrons stopped by thin aluminium sheets they have a moderate ionising ability and a large deflection in electric field

112
Q

Gamma rays

A

A very short wave Electromagnetic waves they are stopped by very thick lead and have a weak ionising ability and then not deflected in an electric field

113
Q

Alpha particles are strongly

A

Positive so they can remove electrons from atoms
When an alpha particle hits an atom it transfers some of his energy to the atom
The alpha particle quickly ionises lots of atoms and loses all its energy and that is why it has a low penetrating power

114
Q

Beta particles have lower charges but higher speeds

A

They can still knock electrons of atoms but they hit atoms less frequently because they’re smaller so they have a better penetrating power

115
Q

Nuclear equations

A

Balance the top and bottom numbers in the equations
14. 14. 0
C N. = e
6. 7. -1

116
Q

Radioactive decay is

A

Random but for radioactive atoms the pattern is best described using the idea of half life

117
Q

Half life

A

The average time taken for half of the atoms in a sample to decay, it has a constant value for any particular isotope

118
Q

Radio active isotopes can be used as

A

Medical traces as it is easy to detect radiation given out

119
Q

Only isotopes are suitable half lives can be used as

A

Medical traces because a very long half life is dangerous as they are exposed to too much radiation but a very short half life is inconvenient
Alpha emitters are no good as they cause damage by ionising atoms inside the body and they wouldn’t be detectable outside the body

120
Q

Radiocarbon dating

A

Measures how much of a particular isotope of carbon there is in a plant or animal this can be used to determine the age of rocks and archaeological finds

121
Q

The last carbon-14 in a sample of organic material

A

The older it must be

122
Q

Hydrogen nuclei combine to

A

Helium nuclei releasing large amounts of energy through nuclear fusion

123
Q

When the hydrogen in a star is called runs out the temperature and pressure of the core starts

A

To rise and it’s all get hot enough to fuse heavier elements

124
Q

Number of moles=

A

Number of particles you have/ number of particles in a mole (Avogadros constant)

125
Q

Molar mass units

A

g mol^-1

126
Q

Calculate the mass of….if …g of … is burnt in air

A

Find molar mass
Number of miles
Mole ratio
Moles x molar mass

127
Q

Empirical formula

A

Gives a smallest whole Number ratio Of atoms in a compound

128
Q

Molecular formula

A

Guess they have a number of atoms in a molecule

129
Q

Empirical formula is a calculated

A

Find number of moles (mass/mr)
Mole ratio
Divide both numbers by the smallest mole ratio
C:H 1:2 mole ratio = CH2

130
Q

To work out the molecular formula

A

At the masses of the empirical formula and see if they equal the molar mass = molecular formula

131
Q

How many electrons can shells hold

A

2
8
8
16

132
Q

Electrons move around the nucleus in

A

Shells or energy levels

133
Q

Atoms in the ground state have all their electrons at their

A

Lowest possible energy levels

134
Q

If an atom is electrons take in energy from the surroundings they can move

A

To a higher energy level further from the nucleus, the electrons become excited

135
Q

Electrons can release energy by

A

Dropping to a lower energy level

136
Q

The energy levels all have certain

A

Fixed values. Electrons can jump from one energy level to another by observing or releasing a fixed amount of energy

137
Q

When electromagnetic radiation is passed through a gaseous element the electrons only absorb

A

Certain frequency is corresponding to differences between the energy levels

138
Q

Absorption spectrum

A

Coloured background and back lines

139
Q

Emission spectrum

A

Black background and coloured lines

140
Q

Absorption spectrum is when

A

An electron moves to a higher energy level and the electrons becomes excited

141
Q

Emission spectrum is seen when

A

Electrons dropped down to lower energy levels and they give out certain amounts of energy

142
Q

🔺E =

A

H x v

143
Q

The difference in energy between two shells (J) =

A

Frequency (Hz) x Plancks constant (Js)

144
Q

Each line in a spectra represents

A

Electrons moving to or from a different energy level

145
Q

As the energy levels get closer together

A

The energy/frequency increases

146
Q

Ionic bonding

A

Is when ions stick together by electrostatic attraction they are formed when electrons are transferred from one atom to another

147
Q

Compound

A

When different elements join and bond together

148
Q

Elements in the same group all have

A

The same number of outer electrons

149
Q

Electrostatic attraction

A

Holds positive and negative ions together and is often very strong

150
Q

How do you show ionic bonding

A

Dot And cross diagram

151
Q

Sodium chloride has a

A

Giant ionic lattice structure

152
Q

A lattice is

A

Cube shaped

153
Q

Ionic compounds conduct

A

Electricity when they’re molten or dissolved. As the ions are free to move where is in a solid at the fixed in position by strong ionic bonds

154
Q

Ionic compounds have high

A

Melting points as they are held together by strong electrostatic forces

155
Q

Ionic compounds are often

A

Dissolved in water, as water is a polar molecule and pulls the ions away from the lattice

156
Q

Ionic bonding is between

A

A metal and a non-metal

157
Q

Covalent bonding is between

A

Two nonmetals

158
Q

Metallic bonding is between

A

TWO metals

159
Q

Date Covalent bonding is where

A

Both electrons come from one atom

So one atom donates both electrons to a bond

160
Q

Molecular substances usually have a fairly low

A

Melting and boiling point as there is no giant structure that needs to be broken down

161
Q

To Melt or boil a simple molecular compound you only have to overcome

A

The attractions between the molecules these are pretty weak compared to ionic covalent bonds

162
Q

Molecular substances don’t

A

Conduct electricity because there are no charge carriers that are free to move

163
Q

Molecular substances are usually

A

Insoluble in water

164
Q

Ionic bonds are usually in the state

A

Solid

165
Q

Simple covalent bonds are usually in the state

A

Liquid or gas

166
Q

Giant covalent structures examples

A

Diamond which is made of carbon and silicone dioxide which is made of silicone

167
Q

Giant covalent structures have very high

A

Melting points as you need to break a lot of very strong bonds before they melt

168
Q

Giant covalent structures are often extremely

A

Hard

169
Q

Giant covalent structures are good

A

Thermal conductors

170
Q

Giant covalent structures won’t

A

Dissolve so they are in soluble in polar solvents like water

171
Q

Giant covalent structures can’t

A

Conduct electricity

172
Q

In metallic lattice is the electrons in the outer most shell of the metal atoms

A

Are delocalised- this leaves a positive metal ions and a sea of delocalised electrons around it

173
Q

In metallic bonding The positive metal ions are attracted to the

A

Delocalised negative electrons

174
Q

Metallic bonding has a high

A

Melting point because of the strong metallic bonds

175
Q

The more delocalised electrons per atom the stronger

A

The bonding will be in the higher the melting point

176
Q

As there are no bonds holding specific ions together the metal ions can

A

Slide over each other when the structure is palled and an example of this is graphite which is very ductile

177
Q

The delocalised Electrons can pass kinetic

A

Energy to each other making metals good thermal conductors

178
Q

Metals are good electrical

A

Conductors because the delocalised electrons can carry a current

179
Q

Metals are in

A

Insoluble

180
Q

Electrons are all negatively charged so they will

A

Repel each other as much as they can

181
Q

Lone pairs of electrons repel

A

More than bonding pairs

182
Q

The greatest angles are between

A

Lone pairs of electrons

183
Q

Bonding pair to a bonding pair bond angles

A

Are the smallest angles

184
Q

Electron pair repulsion principal

A

Is well electrons repel each other as much as they can with the lone pairs repelling more than the bonding pairs

185
Q

No lone pairs has a bond angle

A

Of 109.5

186
Q

One lone pair has a bonding angle of

A

107

187
Q

To lone pairs has a bond angle of

A

104.5

188
Q

A linear molecule has a bone angle of

A

180°

189
Q

Three electron pairs on a central atom has a bond angle of

A

120°

190
Q

A non-linear shape with a lone pair of electrons forms a

A

Bent shape

191
Q

For electron pairs on a central atom with no lone pairs forms a

A

Tetrahedral shape

192
Q

For electron pairs on a central atom with a one lone pair forms a

A

Trigonal pyramid

193
Q

Six electron pairs on a central atom forms a

A

Octahedral shape

194
Q

In the 1800s there was only two ways to categorise elements

A

By the physical and chemical properties and by the relative atomic mass

195
Q

John Newlands

A

Arrange the elements in order of mass, similar elements appeared at regular intervals every eight element was similar this was called the law of octaves

196
Q

Mendeleev

A

Left some gaps in the periodic table where elements didn’t seem to fit, He was then able to predict the properties of the missing elements by comparison with other elements in the same group

197
Q

The modern periodic table

A

Arranges elements by proton numbers

198
Q

All the elements within a period

A

Have the same number of electrons shells

199
Q

All the elements within a group have the same

A

Number of electrons in the outer shell

200
Q

Properties often change gradually as you go

A

Down each group

201
Q

For metal is melting and boiling points increase

A

Across the period because the metal metal bonds become stronger because the metal ions have an increasing number of delocalised electrons and a decreasing radius this leads to a higher charge density which attracts the ions together more strongly

202
Q

Intermolecular forces are weak

A

And easily broken so these elements have low melting and boiling points

203
Q

More atoms in a molecule mean stronger

A

Intermolecular forces

204
Q

The noble gases have the lowest

A

Melting and boiling points because they exist as individual atoms resulting in very weak intermolecular forces

205
Q

Group 2 elements react with

A

Water to produce hydroxides

206
Q

Group 2 elements get increasingly

A

Reactive down the group because the outermost electrons are furthest from the nucleus and so more easily lost

207
Q

Group to oxides and hydroxides are

A

Bases

208
Q

The oxides of the group to metals react readily with water to form

A

Metal hydroxide which dissolve

209
Q

If the solution contains hydroxide ions the solution is strongly

A

Alkaline

210
Q

The oxides for more strongly alkaline solutions as you go

A

Down the group because the hydroxide to get more soluble

211
Q

Group 2 elements that contain single charge negative ions (OH-)

A

Increase in solubility down the group

212
Q

Group 2 elements that contain doubly charged negative ions (CO3^2- and SO4^2-)

A

Decrease in solubility down the group

213
Q

Group 2 carbonates decompose

A

To form the oxide and carbon dioxide

214
Q

The more thermally stable a substance is the more

A

Heat it will take to break it down

215
Q

Thermal stability increases

A

Down the group

216
Q

Carbonate ions are a large onions and can be made unstable by the presence of a

A

Cation

217
Q

A cation draws the electron on the carbonate ion towards itself (polarises it) this then

A

Distorts the carbonate ion and the greater the distortion the less stable the carbonate ion is

218
Q

Large cations cause less

A

Distortion

219
Q

The further down the group 2 the larger the

A

Cations and the less distortion cause and the more stable the carbonate anion is

A// Chemistry (5 decks)

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