Topic 1 & 3 Flashcards
Nucleon number
Atomic number
N (mass):
- num of protons and neutron
- in the nucleus of one atom of an element
A (proton):
- the number of protons
- in the nucleus of one atom of an element
Proton Relative mass, relative charge
Neutron
Electron
Relative mass, relative charge
P 1, +1
N 1, 0
E 1/2000 (0.0005), -1
Isotope definition (2 m)
- ATOMS with the same num of protons/atomic num
- but different num of neutrons/mass num
Relative Atomic mass
definition (3 m)
(Ar)
- the avg mass of all the isotopes of an element
- taking into account their percentage abundance,
- relative to carbon-12
Calculating Ar
(mass num x % abundance) + … / 100
Period num & group num
period num = num of electron shells
group num = num of electrons on outer shell
Group 1
Alkali metals - they all react in a similar way as they all have 1 electron in their outer shell.
Group 2
Alkaline earth metals - react in a similar way:
2 electrons
in outer shell
Group 7
The Halogens - react in a similar way
7 electrons
in outer shell
Group 8/0
The Noble Gases
unreactive/ inert:
they have a full outer electron shell.
Properties of metals (6)
- malleable(can change shape easily)
- good conductors of heat and electricity (electrons are free to move)
- sonorous (make a sound when hit)
shiny
ductile (stretch)
high melting point - A lot of heat energy is needed to overcome forces and break strong metallic bonds in giant metallic structures
properties of non-metals (5)
dull brittle poor conductors - fixed electrons not sonorous low melting point - weak intermolecular forces between the molecules
Ionic bonding
(metal + non-metal)
- The electrostatic force of attraction between oppositely charged
- ions
Describe, in terms of electrons, how an ionic bond in [sodium chloride] is formed. (3 m )
- electron transfer
- from sodium to chlorine
- sodium has lost 1 electron (oxidised) and chlorine has gained 1 electron(reduced).
Relative Molecular Mass definition
(Mr)
sum of the relative atomic masses.
Element definition
Substance that cannot be broken down into anything simpler/
substance containing atoms with the same atomic number or proton number
Ionic bonding
structure & physical properties: conductivity and melting point
Structure: giant crystal lattice
(continuous ions) (regular, pattern of oppositely charged ions)
Properties:
- High melting point (solids at room temp)
- requires large amount of energy to overcome
- the STRONG
- electrostatic forces of attraction between oppositely charged ions. - Can conduct only when MOLTEN or in SOLUTION(dissolved)
- ions
- are free to move
Which has the highest melting point out of NaCl and MgO? (3 marks)
- MgO has the higher melting point
- greater charges of the Mg2+ ion and O2- ion relative the Na+ and Cl-
- therefore stronger forces of attraction between ions in MgO
Covalent Bonding definition (2 m)
The electrostatic force of attraction between
- a shared pair of electrons and
- the positively charged nucleus of EACH ATOM
Molecule definition (2 m)
- a discrete number of atoms
- covalently bonded
Properties of covalent molecules: structure, m & b points, conductivity
simple molecular structure (except diamond..etc)
(simple = discrete number of atoms molecular = atoms covalently bonded)
Low m & b points:
- weak
- intermolecular forces of attraction
- require little energy to overcome
Do NOT conduct - no charged particles that are free to move
Solubility and Volatility of ionic and covalent compounds, monatomic, simple molecular, metallic
Volatility (A substance capable of readily changing from a solid or liquid form to a vapour)
All insoluble except ionic Ionic - soluble, non-volatile (strong ionic bonds) Covalent - insoluble, volatile Monatomic - insoluble Simple molecular - insoluble Metallic - insoluble (reacts with water)
Allotrope definition
different forms of the same element
Diamond structure
C (s)
- tetrahedral arrangement around each carbon
- giant covalent structure
- each carbon is covalently bonded to 4 others
Diamond physical properties
- Extremely high melting, boiling points/ sublimation point:
- giant covalent structure
- many strong
- covalent bonds
- requires high amounts of energy to overcome - Extremely strong: same
- Does not conduct electricity:
- no free electrons
- that can move
Graphite structure
- hexagonal layers of carbon atoms
- giant covalent structure
- layers can easily slide (due to weak forces of attraction between the layers)
- each carbon is covalently bonded to 3 others
Graphite physical properties
can act as what?, conductivity, melting/boiling point
- Soft/ Can act as a lubricant
- layers can easily slide
- due to the weak forces of attraction between the layers - Good conductor of electricity
- sea of delocalised electrons
- that are FREE TO MOVE
can be used in electrodes, brushes in electric motors - Has a high m point/ sublimation point
- giant covalent structure
- many strong
- covalent bonds
- requires high amounts of energy to overcome
Metallic bonding definition (2 marks)
the electrostatic forces of attraction between
- the sea of delocalised electrons
- and the fixed metal cations (+ve ion)
Metallic bonding structure
- giant metallic structure
- cations are regularly arranged in layers
- strong metallic bonds
Metallic bonding physical properties
melting point, conductivity
- High melting point:
- a lot of energy is required to overcome
- the strong
- metallic bonds - Can conduct electricity & heat:
- the sea of delocalised electrons are
- FREE TO MOVE - Malleable (able to change shape without breaking)
- the layers of metal cations are regularly arranged
- can easily slide
What are alloys and why are they stronger than their corresponding metals?
mixture of 2 or more elements/compounds physically mixed.
- the metal cations are irregularly arranged
- so can no longer slide over each other
Uses of mild steel [2] and stainless steel [2]
Name the uses of and stainless steel (chemical plant and cutlery)
Iron and Carbon
mild steel - car bodies and machinery - durable, strong and malleable
stainless steel (20% chromium & 10% nickel) - chemical plant and cutlery - strong and resistant to corrosion, hard
Aluminium alloys uses (3)
- planes - low density to high strength ratio
- food containers - resistance to corrosion
- overhead cables - low density to high strength ration, good conductor, resistance to corrosion
Silicon (IV) oxide
Structure, properties, conductivity
Structure
- tetrahedral arrangement with one silicon atom and four oxygen atoms
- each oxygen atom forms covalent bonds with 2 silicon atoms and
- each silicon atom in turn forms covalent bonds with 4 oxygen atoms
same properties as a diamond
- Extremely high melting, boiling points/ sublimation point:
- giant covalent structure
- many strong
- covalent bonds
- requires high amounts of energy to overcome - Extremely hard & strong: same
- Poor conductor/ Does not conduct electricity:
- no free ELECTRONS
- that can move - insoluble
a mole
1 mole of a substance contains 6.02 x 10^23 particles (Avogadro’s number)
Empirical Formula definition
The smallest whole number ratio of atoms in a compound
% yield
actual/ theoretical x 100
% purity
pure yield/ total yield x 100
give 2 major uses of sulfur dioxide (2)
- Manufacture of sulfuric acid
- bleach
- making paper
food/ fruit juice/ wine preservative
fumigant/sterilising
Brass consists of
zinc and copper
state 2 uses of graphite which depend on the above properties
soft, good conductor of electricity
it is soft: pencils or lubricant or polish
good conductor: electrodes or brushes (in electric motors)
why do sodium ions have a charge of +1? [1]
(they all have) 1 more proton than electrons / 11 protons and 10 electrons
Aluminium is used to make food containers because it resists corrosion. Explain why is it not attacked by the acids in the food. [2]
protective/unreactive/resists/prevents corrosion/non-porous(layer) [1]
of (aluminium) oxide [1]
3 uses of copper
- electrical wires - good conductor of electricity, malleable
- cooking utensils - low reactivity, good thermal conductivity
uses of zinc 2
creates corrosion resistant, tough and conductive alloys = galvanising, making brass(Cu + Zn)
