chemistry

the metal will lose its outer electron/s and become negatively charged, whereas the non-metal will gain these electron/s, and become negatively charged

what happens when a metal and a non-metal react (ionic bonding)

metal positive ions

cation

non-metal negative ions

anion

electrostatic forces hold the ions together. These ions are oppositely charged, meaning they attract each other.

what are the forces in an ionic bond?

very high melting points, brittle, many dissolve in water, form crystals

what are the properties of ionic structures (lattice structures)

they react with water to form metal hydroxides, which are akalis.

why are the alkali metals called alkali metals?

malleable, conduct electricity, relatively low melting points, soft-easily cut, very reactive and readily form compounds with non-metals (ionic compounds), easily oxidised, burn brightly in air

what are the properties of group 1 akalis?

dissolves, bubbles fiercely on the surface, produces hydrogen gas and lithium hydroxide.

what is lithium's reaction with water?

melts into a ball, effervescence, burns with a yellow flame, produces hydrogen gas and sodium hydroxide

what is sodium's reaction with water?

bursts into flames, melts, flies about the surface, burns with a lilac/purple flame, produces hydrogen gas and potassium hydroxide.

what is potassium's reaction with water?

2Li(s) + H20 (l) --> 2LiOH (aq) + H2 (g)

what is the equation for the reaction of a metal (e.g Lithium) with water?

it increases, as group 1 metals have to lose an electron to become stable, meaning as the atoms expand due to more electron shells being added, the distance between the outer electron and the nucleus increases, decreasing FOA, meaning the outer electron can be lost easier.

does reactivity decrease or increase down the group?

halogens, all exist as diatomic molecules, with two atoms held together by a single covalent bond (TWO NON METALS)

group 7

non-metallic (so poor conductors of heat and electricity), toxic and corrosive

what are the properties of group 7 halogens?

yellow gas MP: -101 BP: -35

what is the appearance at room temp, MP and BP of chlorine?

reddish-brown liquid (volatile) MP: -7 BP: 55

what is the appearance at room temp, MP and BP of bromine?

shiny-grey solid MP: 114 BP: 175

what is the appearance at room temp, MP and BP of iodine?

MP + BP increase, as atoms get larger, due to added shells, meaning intermolecular forces get stronger, density increases, colour gets darker

what happens as you go down group 7?

halogens refer to elements, and halides refer to the compound

what is the difference between halogens and halides?

Cl2 (g) + Mg (s) --> MgCl2(s)

example of the ionic compounds called salts:

if damp blue litmus paper is places in chlorine gas, it will first turn red, indicating the chlorine is acidic, as it reacts with the water to form acidic substances, then bleaches the litmus paper due to the acidity.

describe the test for chlorine:

-

reactivity decreases, as halogens need to pull in an electron, but as the atoms get larger as you go down, the outer electron shell is further away from the central nucleus, meaning the FOA between the outer electron and nucleus are weaker, so it is harder for an electron to be pulled in.

explain the trend in reactivity as you go down group 7

a more reactive halogen takes the place of a less one to form a halide compound

what happens in a displacement reaction?

Cl2 (aq) + 2NaBr (aq) --> Br2 (aq) + 2NaCl (aq)

what is an example of a displacement reaction?

when oxidation (loss of electrons) and reduction (gain of electrons) occur together at the same time

what is redox reaction?

when a fluorine atom and a chloride atom react, the fluorine takes an electron off the chloride ion, as it is more reactive and readily forms compounds.

state an example of a redox reaction

they are colourless, with very low MPs and BPs, non-metallic, so they are very poor conductors of heat and electricity.

what are the properties of Group 0 Noble Gases?

they already have full outer electron shells, meaning they do not need to react with anything to lose or gain electrons. Therefore, they all exist as single atoms, because they do not form bonds easily with other atoms.

why are noble gases inert?

density increases, MPs and BPs increase

describe the trend in physical properties of noble gases as you go down the group

Used in photography as it produces a brilliant white light when electricity is passed through it.

what is Krypton used for?

It is added to the space above wine barrels to stop oxygen reacting with the wine (argons is quite unreactive) as it is denser than air.

what is Argon used for?

it is used in weather balloons and airships as it is less dense than air and non-flammable.

what is Helium used for?

Produces a distinctive orange light when electricity passed through it, used for long-lasting illuminating signs

what is Neon used for?

he first said that all elements are made of atoms, atoms are not formed of any smaller particles and all atoms of the same element are identical.

describe Dalton's model

all atoms contain three subatomic particles (neutrons, electrons and protons) and isotopes are different atoms of the same element, yet they are not identical, as they have a different number of neutrons.

why is Dalton's model incorrect?