CHAP 12 THE REACTIVITY SERIES

Question 1

metals are malleable & ductile. what is the definition & reason of malleable & ductile ?

Answer 1

malleable: can be bent, shaped & made into sheets
ductile: can be stretched and drawn into wires without breaking
reason: the atoms in metals are orderly arranged in layers and the layers of atoms can slide over one another easily when a force is applied.

Question 2

why are metals good conductors of electricity?

Answer 2

due to the presence of free moving electrons in the metallic structure ( sea of delocalised electrons )

Question 3

why do metals have high boiling & melting points?

Answer 3

large amount of energy was needed to overcome the strong metallic bonds

Question 4

which metal have the exceptions of high & low boiling point with low density?

Answer 4

mercury ( liquid at r.t.p )

Question 5

why do most metals have high densities?

Answer 5

metal atoms are closely packed together in a regular arrangement.

Question 6

which group of metals have low densities?

Answer 6

group 1

Question 7

metals lose electrons , are they positively or negatively charged ions?

Answer 7

positive ions

Question 8

what do metals and acids react and form?

Answer 8

salt & hydrogen gas

Question 9

what are the three metals that do not react with acids?

Answer 9

copper
silver
gold

Question 10

what oxides do metals react with oxygen form?

Answer 10

basic & amphoteric oxides

Question 11

what kind of compounds do metal form with non metallic elements?

Answer 11

ionic compounds

Question 12

what are examples of amphoteric oxides?

Answer 12

Lead (Pb)
Aluminium ( AL )
Zinc ( Zn )

Question 13

what are alloys?

Answer 13

alloys is a mixture of a metal and other elements ( can be metal/ non metal )

Question 14

what are 3 examples of alloys?

Answer 14

mild steel - iron & carbon
brass - copper & zinc
bronze - copper & tin

Question 15

why are pure metals soft?

Answer 15

pure metals are soft as the atoms are orderly arranged in layers and the layers of atoms can slide over one another easily when a force is applied

Question 16

why are alloys stronger than pure metals?

Answer 16

alloys are made up of atoms of different sizes. This disrupts the orderly layers of atoms making it harder for the layers of atoms to slide over each other when a force is applied.

Question 17

what are the 3 uses of alloys?

Answer 17

1) mild steel. - iron & carbon -> strong & malleable
[ car bodies , steel rods ]
2) stainless steel - nickel , iron , chromium, carbon [NICC] -> non corrosive , rust resistant [ cutlery , utensils & surgical instruments ]
3) brass - copper & zinc -> non corrosive
[ coins , decorative ornaments ]

Question 18

what is the reactivity series?

Answer 18

measures how readily a metal give up electrons to form positive ions

Question 19

do reactive metals lose or gain electrons more readily?

Answer 19

lose -> to form positive ions

Question 20

what are the only metals that reacts with COLD WATER?

Answer 20

P otassium ( explosive ) K
S sodium (explosive) Na
C alcium (vigorously) Ca
M agnesium ( slow ) Mg
(Please Stop Calling Me)

Question 21

metals below what element don’t react with water, steam or acids?

Answer 21

hydrogen H
copper Cu
silver Ag
gold Au
[ these three metals are unreactive ]

Question 22

reactive metals + water forms?

Answer 22

metal hydroxides + H2

Question 23

reactive metals + steam forms?

Answer 23

metal oxides + H2

Question 24

metals + acid forms?

Answer 24

salt + H2

Question 25

is it easier or harder to extract a reactive metal from its ore?

Answer 25

harder ( a less reactive metal is easier to extract than a more reactive metal )

Question 26

what are the two methods to extract metals?

Answer 26

- reduce metal compounds to metal by using carbon - use electricity to decompose the molten metal compound to the metal ( electrolysis )

Question 27

in what way can we extract reactive metals such as potassium, sodium, calcium , magnsium and aluminiun?

Answer 27

electrolysis

Question 28

can unreactive metals be found combined or uncombined on earth?

Answer 28

uncombined

Question 29

the more reactive a metal is , the more _____ it is

Answer 29

stable

Question 30

why is electrolysis used on very reactive metals?

Answer 30

-metals are very reactive and hence they are found in very stable compounds with strong ionic bonds. - a lot of energy is needed to overcome the ionic bonds and so electrolysis of molten ore is used.

Question 31

what are the examples of very reactive metals?

Answer 31

P otassium (K) S odium (Na) C alcium (Ca) M agnesium (Mg)

Question 32

what are the examples of LESS reactive metals?

Answer 32

Z inc (Zn) I ron (Fe) T in (Sn) L ead (Pb) H ydrogen (H) C opper (Cu) S ilver (Ag) G ood (Au)

Question 33

why is reduction of oxides using carbon or hydrogen used in extracting less reactive metals?

Answer 33

- metals are found in less stable compounds with fairly strong ionic bonds - lesser energy is needed to break the bonds and so reduction of oxides using carbon or hydrogen is used.

Question 34

gold in an unreactive metal. what methods can be used to extract gold?

Answer 34

physical methods