Topic 6 - groups in a periodic table / SC17

Question 1

What are group 1 metals known as

Answer 1

Alkali metals

Question 2

what are the properties of group one metals

Answer 2

• low melting point
• soft
• easy to cut
• very reactive
  -easily oxidised

Question 3

group one reactions with water:
lithium, sodium, potassium

Answer 3

lithium+water
bubbles fiercely on the surface

sodium+water
melts into a ball and fizzes around the surface

potassium+water
bursts into flames and flies about the surface

Question 4

describe the reactivity of alkali metals

Answer 4

the reactivity increases down group 1/ alkali metals

Question 5

why does the reactivity of alkali metal increase down the group

Answer 5

• they have one electron in the outer shell
• the more down the group, the more shells there are in the atom
• the distance between the one electron in the outer shell and the nucleus increase
• so it is easier to remove the electron therefore become more reactive down the group.

Question 6

why are elements classifies as ( alkali metals and noble gases) in the periodic table?

Answer 6

it is based on there electrons in the element.
varying electrons also causes variations in properties

Question 7

what are group 7 element know as

Answer 7

halogens

Question 8

state at room temp and colour of the following halogens:
fluorine
chlorine
bromine
iodine

Answer 8

flourine - gas + pale yellow
chlorine - gas + yellow - green
bromine - liquid + red-brown
iodine - solid + dark grey

Question 9

the physical properties of halogens

Answer 9

the bp and mp increase down the group

Question 10

what is the test for chlorine

Answer 10

use a damp blue litmus paper
if there is chlorine the paper will go from blue to red to bleached white

Question 11

reactions of the following halogens to with a metal to form metal halides:
chlorine
bromine
iodine

Answer 11

the reactivity of the halogens decrease down the group
chlorine will react in sunlight
but bromine need high temperatures such as a flame to react

Question 12

how hydrogen halides dissolve in water to form an acidic solution

Answer 12

when hydrogen halides dissolve in water they from an acidic solution.
chlorine is easy to make into a acidic solution as it fully dissociates meaning it is a strong acid
iodine is harder to dissociate due to stronger bonds so it is harder to form into an acid

Question 13

describe the relative reactivity of halogens shown through displacement reaction

Answer 13

• chlorine is more reactive than bromine as it is higher in the group.
• chlorine displaces bromine in a redox reaction due to being more reactive

Question 14

explain why displacement reactions are called redox reaction

Answer 14

• there is both oxidation ( loss of electrons) and reduction ( gain of electrons)

Question 15

Explain the reactivity of the halogens in terms of electronic configurations

Answer 15

-going down group 7:
-the outer shell with 7 electron gets further from the nucleus
- the force of attraction between the outer electron shell and the nucleus gets weaker.
- atoms higher up have a greater attraction between its final shell and the nucleus
- making it easier to gain an electron so is more reactive

Question 16

explain why noble gases/ group 0 are inert

Answer 16

• they have a lack of reactivity due to:
• they have full outer electrons
• they have no tendency to lose, gain or share electrons.

Question 17

properties of noble gases

Answer 17

• inert
• low density
  -non flammable

Question 18

uses of noble gases in relation to properties

Answer 18

helium - lifting ballons
inert and low density
argon - filling gas in filament lamps
inert

Question 19

describe trends found in noble gases

Answer 19

the density increases down the group
the bm/mp increases down the group