topic 7 - groups in the periodic table

Question 1

what are the 6 metals in group 1

Answer 1

lithium
potassium
sodium
rubidium
caesium
francium

Question 2

what are 2 physical properties of alkali metals

Answer 2

very soft (cut with a knife)
relatively low melting and boiling points

Question 3

what do alkali metals form

Answer 3

readily lose their single outer electron to form 1+ ions with a stable electronic structure or form ionic compounds

Question 4

what are the group 1 elements called

Answer 4

the alkali metals

Question 5

what is the reactivity of group 1 like as you go down and why

Answer 5

the reactivity of the metals increases, as you go down the group
this is because the outer electron is more easily lost due to the atomic radius being larger so they are less strongly attracted to the nucleus

Question 6

what happens when alkali metals react with water

Answer 6

they react vigorously to produce hydrogen gas and a metal hydroxide

the further down the group, the more violent the reaction becomes

Question 7

how does lithium react with water

Answer 7

moves around on surface

fizzes furiously

Question 8

how does sodium react with water

Answer 8

melts to form a ball that moves around on the surface fizzing rapidly

hydrogen produced may burn with an orange flame before sodium disappears

Question 9

how does potassium react with water

Answer 9

metal melts and floats, moving across surface quickly

ignites quickly with sparks and a lilac flame, sometimes giving a small explosion at the end of the reaction

Question 10

what are the group 7 elements called

Answer 10

halogens

Question 11

trends in group 7

Answer 11

as you go down:
melting and boiling points increase
colours get darker

Question 12

what colour and state is chlorine

Answer 12

green gas

Question 13

what colour and state is bromine

Answer 13

red-brown liquid giving off orange vapour

Question 14

what colour and state is iodine

Answer 14

dark grey crystalline solid that gives off a dark purple vapour if heated

Question 15

group 7 elements exist as diatomic molecules ; what does this means

Answer 15

they share one pair of electrons in a covalent bond, giving both atoms a full outer shell

Question 16

what is the test for chlorine

Answer 16

hold a piece of damp blue litmus paper over the gas

if it bleaches to white, chlorine is present

Question 17

how does reactivity change as you go down the group 7 elements and why

Answer 17

reactivity decreases as it is harder to attract the electron to fill the outer shell as it is further away from the nucleus

Question 18

metal halides

Answer 18

salts formed by reacting halogens with metals

Question 19

hydrogen halides

Answer 19

soluble gases which dissolve to form acidic solutions

Question 20

displacement reaction

Answer 20

a reaction where a more reactive element displaces a less reactive element from a compound

Question 21

how are halogen displacement reactions redox reactions (what is reduced, what is oxidised)

Answer 21

halogens gain electrons (reduced)

halide ions lose electrons (oxidation)

Question 22

how do you use displacement to discover reactivity trends (4)

Answer 22

1) measure a small amount of halide salt solution into a test tube
2) add a few drops of halogen solution and shake gently
3) if there is a colour change, a reaction has occurred
4) repeat with different combinations of halide salt and halogen

Question 23

what are the group 0 elements called

Answer 23

noble gases

Question 24

properties of noble gases

Answer 24

colourless gases at room temperature
all monatomic
more or less inert (unreactive) - therefore non flammable

Question 25

everyday uses of noble gases (4)

Answer 25

used to provide an inert atmosphere (non flammable atmosphere inside filament lamp - argon)
used to provide an inert atmosphere (flash photography - argon, krypton, xenon)
used to protect metals being welded so the hot metal doesnt react with oxygen (argon, helium)
used in airships and balloons (helium)

Question 26

why is helium used in airships and baloons

Answer 26

has a lower density than air , allowing them to float

non-flammable so safer than hydrogen gas

Question 27

patterns in noble gas physical properties (2)

Answer 27

as you go down the group:
melting and boiling point increase
density increases