Chemistry~ 4.1 predicting chemical reactions

What are the properties of group 1, alkali metals?

What are the properties of group 1, alkali metals?

shiny, good conductors. softer and denser as you go down the group, less denser than water, low melting point(that decrease as you go down)

Why are group 1, alkali metals stored in oil?

Because they react quickly with water and oxygen

Metal + water → _____ + _____

metal hydroxide + hydrogen

Lithium reaction with water

Fizzes steadily, gradually disappears

Sodium reaction with water

melts into a silver ball, fizzes vigorously, disappears more quickly

Potassium reaction with water

Ignites (burns) with a lilac flame, disappears very quickly

What colour would you expect universal indicator to be in potassium hydroxide solution?

blue, contains OH- ions

What are the properties of the group 7, halogens?

brittle in solid state, poor conductors, exist as diatomic molecules /w weak intermolecular forces, coloured/form coloured vapours, exist at different states at room temperature

fluorine (F₂) colour

pale yellow gas

chlorine (Cl₂) colour

green gas

bromine(Br₂) colour

orange-brown liquid that vaporises easily

Iodine(I₂) colour

shiny grey-black crystalline (ordered structure) solid that sublimes(s-g) to form purple vapour

What are the trends of group 7 elements going down the group?

density increases, melting and boiling point increase

metal + halide → ____ ____

metal halide

general ionic equation for a halogen

X₂ + 2e¯ = 2X¯

The easier it is for a halogen atom to gain an electron...

the more reactive the element is

Explain shielding with an example (chlorine)

Chlorine atoms are bigger (3 shells), this means the outer electron shell is further away from the nucleus and is shielded from its pull by the inner shells making it harder to gain an electron

How do displacement reactions work?

A more reactive metal can replace a less reactive metal from a compound.

EG of displacement reaction: bromine + potassium iodide =

iodine + potassium bromide

Reactivity series order :

Potassium, Sodium, Lithium, Calcium, Magnesium, (carbon), Aluminium, Tin, Lead, Iron, (hyrdogen), Copper, Silver, Gold, Platinum

What are the trends and properties of transition metals?

from more than one stable ion (EG: iron(II) and iron(III)), traditional metals, form coloured compounds, good catalysts

Metal + oxygen → ____ ____

metal oxide

metal + acid → ____ + ____

salt + hydrogen

What are the trends and properties of group 0, noble gases?

gases, monoatomic, unreactive/inert, density and boiling point increase as you go down the group, glow with different colours when electricity is passed through them, larger atomic molecules have stronger intermolecular forces

uses of noble gases?

MRI scanner, light bulbs, carrier gas (in gas chromatography)