Chemistry 4 - Classifying material Flashcards
Shielding is what
Attraction from the nucleus of the electron is decreased when there are loads of “INNER ELECTRONS” in the way
meaning the further out the electron is the less attraction due to increased shielding
Isotopes are what
Different forms of the same element with several more/less neutrons which changes the mass number
Relative atomic mass shows what
How much of each isotope there is compared to the total amount of the element in the world
RAM =
sum of the relative abundances
Ionic compounds always have what
Giant ionic lattices
Ionic Compounds all have what properties (2)
High melting/boiling point
Which groups on the periodic table most likely form positive ions
negative ions?
groups 1 /2
Groups 16/17
The charge formed (+1 , -2) is the same as what
The group they are found in
Group 1 metals are known as what
Alkali metals
When alkali metals are cut, what does it look like?
However over time what happens?
Shiny
Reacts with oxygen which tarnishes it
The lower down in the alkali sequence, what happens to the boiling/melting point and the density
lower melting/boiling point
Higher density
When alkali metal is placed in water, what two things forms?
metal hydroxide (sodium hydroxide)
and hydrogen
How do you know if hydrogen is present from the alkali metal reaction with water
lighted splint creates squeeky pop
Alkali metals always form what type of bond
Ionic bond
What sort of compound is created iwth alkali metals in terms of colour
what can it dissolve in to form?
White compound
dissolves in water to produce colourless solution
Group 17 are known as what
Halogens
Going down group 17, what happens to the boiling point and melting point?
increase
What happens to the reactivity of group 17 elements going down it
decreaes reactivity
Harder to gain an outer electron as its further away from the nucleus
therefore chlorine is most reactive
What happens to the electronegativity of group 17 elements as you go down the groups
Decreases
The larger the atom, the less the force of attraction
Halogens are all ….. with coloured …..
non metal with coloured vapours
What colour is flourine
Yellow poisonous gas
What colour is chlorine
Green poisonous gas
What colour is bromine
Red-brown volatile liquid posionous
What colour is iodine
dark grey crystalline solid or purple vapour
what bonds are formed with metals as a halogen
Ionic Bond
Halides are what
Negative Ion
Alkali metals and halogens will form what
salts (sodium chloride)
More reactive halogens will … less reactive ones
displace
if KBr is mixed with CL2, what happens?
think displacement
Br2 is formed
Orange Solution formed as Chlorine displaces the bromine
KI and CL2
Brown solution (I2) formed
As chlorine displaces Iodine
KI and Br2
Brown Solution (I2) formed
As Bromine displaces iodine
Noble gases are all (3)
Inert
colourless gases
Non flammable
Argon can be found in what?
why
Provides inert atmosphere in filament lamps
Its non flammable and stops hot filament from burning away
Helium can be found where
Airships/party balloons
as you go down the noble gases, what happens to the densities and boiling points
Both increase (goes from -269 to -62)
Why dont molecular substance conduct electricity
No ions present to conduct charge
covalent structures have high what
they dont what?
Melting/boiling points
Conduct electricity
Why is graphite a good conductor of heat and electrciity
Has one free delocalised electron which can conduct heat/electricity
Why are alloys harder
new metals distort the original layers of metal atoms, making it harder for them to slide over eachother
Increasing hardness
Simple molecular structures will have what properties
Very very low melting/boiling points (-269)
Dont conduct electricity
Giant metallic structures will have what properties
High melting/boiling points
Can conduct electricity
Giant Covalent structures will have what properties
High melting/boiling point
Doesnt conduct electricity
giant Ionic structures will have what properties
Medium melting/boiling points
cant conduct electricity unless molten
What transition metal ised useful for the hydrogenation of alkenes
Nicklel
Iron (II) compound is what colour
Light Green
iron (III) compound is what colour
orange/brown
Copper compounds are what colour
Blue
