✅ Flashcards
Properties of alkali metals
Very reactive Low density Soft Relatively low m and b points Form 1+ ions
Properties of halogens
Low m and b points
Poor conductors of heat and electricity
Reactivity decreases down the group
Characteristics of transition elements
Good conductors of heat and electricity
Hard and strong
Dense
High m and b points
which scientist ordered elements in terms of their weight?
dalton
what did mendeleev do?
created perdiodic table based on atomic weight and left gaps for undiscovered elements
what are elements in order of in the periodic table?
proton number
what does the group of an atom tell us
the number of electrons in outer shell
main difference between metals and non metals
metals conduct electricity where most non-metals are insulators
where are non-metals found?
rhs
what is different about noble gases?
have full outer shell
how do metals react?
losing outer electrons
how do non-metals react?g
gaining electrons
what determines an elements chemical properties
number of electrons in outer shell
what happens in a halogen displacement?
a more reactive halogen displaces a less reactive halogen from its salt
why does reactivity increase going down group 1?
they need to lose one electron which is easier the further away it is from the centre
why does reactivity decrease going down group7
they need to gain one electron but the forces pf attraction are weaker in the outer shells
properties of transition metals?
good conductors
hard
dense
high melting points
what are transition elements often used as
catalysts
What did dalton do to create the periodic table?
Arranged elements in order of atomic weights
What did Newlands do to create the periodic table?
Proposed the law of octaves where the proposer ties of every eighth element were similar
What was Mendeleev’s breakthrough?
He left gals in the periodic table for elements yet to be discovered
How are elements organised in the periodic table now?
By increasing proton (atomic) number
What does the group an element is in tell you!
How many electrons are in outer shell
Why are noble gases very unreactive?
Full outer shell
Reaction of alkali metals with water?
Floats on water
Fizzes
Moves around
What is produced when an alkali metal reacts with water?
Metal hydroxide and hydrogen gas
Why are alkali metals stores under oil?
React with oxygen in air
What do the halogens all exist as
Molecules (pairs of atoms)
What colour is fluorine
Yellow
What colour is chlorine
Green
What colour is bromine
Red-brown
What colour is iodine
Purple
As you go down group 7:
Less reactive
Higher m and b points
Higher rfms
What are the two types of bonds halogens can make
Ionic bonds with metals
Covalent bonds with non metals
Why do halogens get less reactive down the group
Further from nucleus so harder to attract extra electron
What happens in a halogen displacement reaction?
A more receive one will displace a less reactive one from its salt
What ions do halogens form
1-
Why does reactivity increase down group 1?
The atoms get larger so the single electron they want to lose is farther from nucleus
What is the force called between nucleus and electrons
Force of attraction
What sub atomic particle can change force of attraction
Electrons can shield outer electrons from nucleus
Physical properties of transition elements
good conductors
Hard and string
High m points
‘Typical metals’
What is special about ions of transition metals?
Can form 2+ or 3+ ions
How to tell whether 2+ or 3+ ion
Look at Roman numeral
