CHEM MOCK COMBINED

how do metals form ions?

LOSE electron, positive ion

how do non metals form ions?

GAIN electron, negative ions

valency =

charge

zinc ion

Zn²⁺

silver ion

Ag⁺

Hydrogen ion

H⁺

iron (II) ion

Fe²⁺

Iron (III) ion

Fe³⁺

copper (II) ion

Cu²⁺

sulfate ion

SO₄^2-

carbonate ion

CO₃^2-

hydrogencarbonate charge

HCO₃^-

nitrate ion

NO₃^-

Hydroxide ion

OH^-

ammonium ion

NH₄⁺

definition of ionic bond

an ionic bond is an electrostatic force of attraction between positive and negative ions

boiling point of ionic compounds

high

why is boiling point of ionic compounds high

strong electrostatic forces of attraction between the positive and negative ions throughout whole structure which takes lots of energy to overcome

how do ionic compounds conduct electricity

ions

when do ionic compounds conduct electricity

solution/molten

why don’t ionic compounds conduct in solid

ions are in a fixed posision

why do ionic compounds conduct when molten/solution

ions are free to move + carry charge

covalent bond definition

the electrostatic atraction between the shared pair of electrons and the positive nuclei of the atoms either side

covalent - metal or non metal

2 non metals

what are simple molecular structures?

• molecules which are neutral particles

• fixed number of atoms

• strong covalent bonds

  • weak intermolecular forces

melting point of simple molecular

• low melting + boiling point

• weak forces between molecules

• not much energy needed to OVERCOME them

do simple molecular structures conduct electricity?

no

• no charge particles

  • current cannot flow

giant covalent structure

• giant 3d lattice, regular arrangement of atoms

• many strong covalent bonds throughout

• no molecules

diamond structure

• each C bonded to 4 others

• many strong covalent bonds throughout

• no electrons are free to move

melting point diamond

• very high

• many strong covalent bonds = lots of energy

conductivity of diamond

DOES NOT CONDUCT

• no charged particles

  • all electrons involoved in bonding

are diamonds hard?

yes

• rigid 3d structure

  • held together by strong covalent bonds

uses of diamond

• jewelry

• driling + cutting

graphite structure

• each C bonded to 3 others

• atoms in layers

• many strong covalent bonds within each LAYER

• electrons free to move between layers

• forces betweel layers are weak

melting point of graphite

HIGH

• many strong covalent bonds = lots of energy to break

conductivity of graphite

DOES CONDUCT

• there is a delocalised electron per carbon

• free to move + carry charge

why is graphite soft/slippery

• arranged in layers

• weak attraction

  • slide over each other

uses of graphite

• pencils

• electrical componens

• lubricant in industry

• sporting equipment

metallic bond definition

electrostatic attraction between positive metal ions and negative sea of delocalised electron

how to draw bonding

• at least 3 rows positive ions (+ in circle)

• delocalised electrons (- in circle)

• labelled

melting point metallic

high

• strong attraction between positive ions and electrons

• lots of energy to overcome

electrical conductivity metallic

• conducts

• delocalised electrons free to move + carry current

strength of metallic

strong but malleable

• bonds strong

• layers of ions can slide

metallic solubility?

insoluble

what is an alloy

mixture of a metal with small amounts of other elements

why are alloys harder than pure metals?

layers cannot slide over eaxh other so easly as atoms are different sizes

why are noble gases inert

they have a complete outer shell, so don’t need to react

why is argon used for food packaging

unreactive, not toxic

why is argon used for welding

unreactive and not flammable

properties unique to alkali metlas

• very reactive with oxygen and water- stored in oil

• shiny when cut, quickly dulls

• low density (some float on water)

• low melting point for a metal

• mainly form white compounds which are soluble in water

why do alkali metals have similar properties

they all have 1 outer shell electron, and react by losing it

observation of lithium and water

fizzes, floats on surface, gently moves, disappears (universal indicator turns purple)

sodium and water is same as lithium but…

melts into a ball, moves faster

potassium same as sodium but…

moves faster, lilac flame and sparks (H igniting)

why do alkali metals get more reactive as you go down group

• react by losing outer electron

• as you go down, atoms get larger

• this means electron is further away from nucleus

• there is less attraction

• electron is lost more easily

halogen are __ non metals and are all _

reactive

toxic/harmful

fluorine state + colour

gas , pale yellow

chlorine state + colour

toxic gas, pale green

bromine state + colour

volatile liquid, red-brown

iodine state + colour

brittle solid, dark grey

astatine state + colour

solid black

halogen ions are

halides

hydrogen chloride state , solubility, what happens in water?

gas, soluble, dissociates in water to form hydrochloric acid

how to halogens react?

gain an electron

why do halogens get less reactive going down group

• atoms get bigger

• outer electron further from nucleus

• attraction is weaker

• extra electron is less easily gained

group no.

number of electrons in outer shell

period no

number of shells

water

• formula

• % 

• properties

• uses

• H₂O

• varies

• polar molecule

• required by living creatures

uses of carbon dioxide + why (property)

• fizzy drinks - soluble in water

• fire extinguisher - denser than air, doesn't support combustion

• refridgerant - dry ice, solid co2, sublimes so no wet cardboard

Unburned fuels

• how formed 

• problems

• solutions

• incomplete combustion 

• breathing problems, less efficient 

• ensure correct fuel:air mixture when fuel is burned

test for CO2 

• bubble through limewater

• solution will go from colourless to cloudy 

sulfur + oxygen 

• word equation

• basic or acidic

• what do you see

• sulfur + oxygen ---> sulfur dioxide

• acidic

• glows blue

sodium+ oxygen 

• word equation

• basic or acidic

• what do you see

• sodium + oxygen ----> sodium oxide 

• basic 

• yellow flame + white smoke

SO₄ sulfur dioxide

• how formed 

• problems

• solutions

• sulfur impurity burns with fossil fuels

• acidic rain: damages plants, kills fish, corrodes limestone

• remove SO4 by flue gas desulfurisation

phosphorous to find percentage of oxygen in air 

percentage of oxygen in the air using iron

oxygen

• formula

• % 

• properties

• uses

• O2 

• 20%

• very reactive, required for respiration

• hospitals - patient breathing

NO/NO₂ Nitrogen oxides 

• how formed 

• problems

• solutions

• car engines - N₂ in air is reacting at high temos

• acid rain

• catalytic converters 

Nitrogen

• formula

• % 

• properties

• uses

• N₂ 

• 78%

• unreactive

• food packets

melting point of CO₂ and explanation

low - weak intermolecular forces between molecules
co2 is simple molecular bonding

Magnesium + oxygen 

• word equation

• basic or acidic

• what do you see

• magnesium + oxygen ----> magnesium oxide

• basic

• bright white light + white powder

is co2 soluble in water?

yes

in general, metal oxides are _____ and non-metal oxides are ____

basic, acidic

CO2 - carbon dioxide 

• how formed 

• problems

• solutions

• complete combustion of c in fuel

• greenhouse gas causing global warming

• burn less fossil fuels

CO - Carbon monoxide 

• how formed 

• problems

• solutions

• incomplete combustion of C in fuel

• TOXIC

• ensure good supply of air/oxygen when burned

carbon dioxide

• formula

• % 

• properties

• uses

• CO2

• 0.03%

• unreactive

• fire extinguishers

carbon + oxygen 

• word equation

• basic or acidic

• what do you see

• carbon + oxygen -----> carbon dioxide

• acidic

• glows red

C soot/particulates

• how formed 

• problems

• solutions

• incomplete combustion of C in fuel

• blackens buildings, global dimming, breathing issues

• ensure there is a good supply of oxygen/air when burned

Argon

• formula

• % 

• properties

• uses

• Ar

• 0.9%

• very unreactive

• inside filament lightbulbs

appearance of carbon dioxide

colourless gas

alkenes test/result

-reacts with Br2(aq) immediately (addition reaction)

• alkenes go colourless in bromine water

• addition of halogens=test for double bonds

crude oil

a mixture of hydrocarbons

alkanes test/reactions

• alkanes react with Br2 (aq) in presence of uv light (goes colourless)

• undergoes substitution reaction

functional group

part of an organic molecle responsible for it’s chemical reaction

alkene general formular and functional group

• C_nH_2n

• C=C

molecular formular

• exact number of atoms

empirical formula

• simplest ratio

displayed formula

shows all atoms and all bonds