c2- the periodic table Flashcards
periodic table are arranged in columns called
and what ae periods ,
groups
rows
where are the trasition metals ?
se to zn .
where are the non metals ?
A staircase from aluminium .
Why is it called the periodic table ?
As it is arrnaged with elements with similar propeorties at regular intervals .
All elements in a group have …
simialr chemical propeorites .
-they all reacti in a similar way - as all the lements ina group have the same number of electrons in their outer energy level .
What did Johann Dobereiner notice ?
-He noticed that elemnts with similar properties often occured in threes , these are called “triads”.
What happend 40 years after Johann ?
John Newlands arranged the elements in order of increasing atomic weiht .
-He saw that every eight elemnt react in the ame way - called this his law of octaves .
Problem with John Newlands idea .
-y always sticking to the exact order of the atmoic weight
some elements grouped and togther and they had totally differnet propeorties ,
-meant that law of octaves wasnt taken seriously y other scienitsts .
What Dmitri Mendeleev do ?
-e devloped the first modern Peroidic table .
-Mendeleev started by arranging the elemnts in order of increasign atmoic weight .
What Dmitri Mendeelv do that ONLY he did ?
-If he needed to swwitch the order of speicific elements , he did so it fitted patterns of elements in the same group .
-also realised , some elemnts have not been yet discovered , so he left gaps for them
what happened next with mendeelev’s gaps ?
-as he was so confident in his periodi ctabe , he actulaly predicted propeorties of some undiscovered elements , when they later were found , mendeleev’s predcitions were correct .
What was one way the modern periodc table differs from Mendeeleev;s .
The modern periodic table , elements arranged in order of atmoic number . (protons werent discoevrred tthen so mendeelev ordered in ATMOIC WEIGHT ).
What is the problem with ordering in atomic weight ?
-Elements can appear in wrong order due to presence of isotopes .
What is another way the modern periodic table differs from Mendeelev’s ?
The modern periodic table has group 0 ; noble gases (had not been discoevred when Mendeleev published his table ).
What are group 1 metals called ?
The alkali metals .
-All group 1 metals havw 1 electron in their outer enegry level .
-group 1 metals are soft .
-low melting points and densities
-form 1+ions
Hhow do group one metals react with oxygen .
all group 1 metals react rapidly with oxygen .
group 1 metals react more rapidly as we move down group 1 .
Write symbol equation for group 1 metals reacting with oxygen .
4Li+O2—->2Li20
change the metal for all others group 1 metals .
How do group 1 metals react with chlorine .
React rapidly with chlorine .
2Li+Cl2—>2iICl
DIATOMIC CHLORINEEEE
change the metal for all other group 1 meals .
How do group 1 metals react with water ?
-Universal indicator in water .
Lithium reatcs rapidly with water (more rapid down g1)
-fizzinng (hydrogen produced ).
universal indicator goes purple showing ALKALINE prsent hence alkali metals .
State symbol and word equation for alkalines reacting with water .
Lithium + water — > Lithium hydroxide +hydrgoen
Lithium hydroxide is a alkaline hence pirple colour , hydrogen is the fizzing effervescence .
2li +2H20—>2LIOH+H2
change for different metals in different metls .
As we move down group 1…
metals get more reactive .
g1 looses ouer electron when they react .
-As we move down the group the outer electron is less attarcted to the nucleus and easier to loose .
-As there is a greater distance beween positive nucleus and negative outer electron .
-The outer electron is shielded from the nucleus’s intenral energy levels .
What are elemnts in group 7 known as ?
The halogens .
How manye elctrons do Group 7 elemnts have ?
They have 7 electrons on their outer shell .
How do group 7 elemnts form molecules ?
Form molecules with two atoms joined bby a covalnet bond .
What temperature is roomt temperature .
20 degrees .
As you go down group 7 , the melting and boiling point …
Increase .
What are Fluorine and Chlorine at Room temperature ?
Gases at room tempeatrue as their melting and boling points less than 20 l.
What is Bromine at room temperature ?
Liquid , meltin point lower than 20 , but boiling point higher than 20 .
Iodine at room temperature ?
Idoine is a solid , but metling and boiling point higher than 20 .
The relative molecule mass of group 7 …
Increases as you go down gthe group
Group 7 elemnts form covalent compounds when they react wwith other non-meals . .
Grooup 7 non -metals react with metals to form …
ionc compounds .
-the gain one electon also .
so have an overall 1minus charge when they react with METALS . end in ide instead of INE as well .
What is the reactivity series in group 7 ?
The elems get less reactive as you gown the group.
Chlrine gains electron less easily than fluroine WHY ?
-Greater neergy level from nucleus
-shieldign bby internal electors .
-harder for chlrine to attarct an electron than for fluroine .
displacement reactions in Halogens abt reaction ?
-A more reactive halgoen will displace a less reactive halogen froma n aqueous solution of its salt .
Example of key rule in Halgoen displacement reactions .
Fluorine+Sodium Chloride —>Sodim fluoride+chlorine
Chlorine gets displaced as Fluorine is MORE reactive .
What are transition metals ?
-Hard and strong metals .
-HIgh melting point (mercury excepition )
-HIgh denisty .
What are transition metals (2)
-Much less reactive than group 1 metals (with oxygen chlorine and water .)
-can form ions with differen charged
-form coloured copounds
-used as catlaysts .
Example of coloured compounds in Transiiton metals ?
Iron oxide (III) Reddish
Manganese Chlirde (II) Pink
Chromium Chloride (III) Purple
