The Periodic Table and Group Trends

Question 1

How to extract group 1 metals

Answer 1

extracted by electrolysis of molten compounds

Question 2

what are the group 1 metals called

Answer 2

alkali metals

Question 3

physical properties of alkali metals

Answer 3

soft - cut with knife
low melting and boiling points
surface is shiny/silvery grey but tarnishes quickly
floats on water

Question 4

what type of bonding is used for group 1

Answer 4

metallic bonding - relatively weak compared with other metals

Question 5

reactivity of group 1 metals

Answer 5

very reactive - stored in oil to prevent reaction with oxygen or water in the air
react vigorously with water forming

Question 6

group 1 metals what happens to k

Answer 6

k is more reactive - catches fire, lilac flame, pops as hydrogen ignites

Question 7

why does reactivity increase going down alkali metals

Answer 7

outer electron has to be lost to form positive ion. further the outer electron is from the nucleus, the less tightly it is held. it is shielded from the nucleus by full inner shells and so is more easily removed

Question 8

what are group 7 metals known as

Answer 8

halogens

Question 9

appearance of fluorine

Answer 9

gas - pale yellow green

Question 10

appearance of chlorine

Answer 10

yellow green gas

Question 11

appearance of bromine

Answer 11

red liquid (volatile)

Question 12

appearance of iodine

Answer 12

silvery grey solid

Question 13

why do halogens have low melting points

Answer 13

they are simple covalent molecules and only have weak intermolecular forces that need to be overcome

Question 14

why do boiling points increase down the halogens

Answer 14

molecules get bigger so the intermolecular forces get stronger due to more electrons in the molecule

Question 15

where must chlorine be used due to toxicity

Answer 15

fume cupboard

Question 16

extraction of chlorine

Answer 16

electrolysis of concentrated NaCl solution (2NaCl + 2h2o -> 2NaOH + H2 + Cl2

Question 17

extraction of bromine and iodide

Answer 17

from their salts by displacement using cl2

Question 18

test for chlorine

Answer 18

damp blue litmus paper pink then bleaches it

Question 19

uses of chlorine

Answer 19

killing bacteria
bleach in paper making
production of antiseptics

Question 20

what do halogens react with h2 to make

Answer 20

hydrogen halides

Question 21

what are the noble gases

Answer 21

group 0/8

Question 22

have full outer shells of electrons so

Answer 22

do not react

exist as single atoms

Question 23

how are noble gases obtained

Answer 23

fractional distillation of air

Question 24

use of helium

Answer 24

weather balloons

airships - low density and flammability

Question 25

use of argon

Answer 25

welding to stop hot molten metal oxidising

Question 26

use of neon

Answer 26

fluorescent lights

Question 27

use of ar/kr/xe

Answer 27

inert atmosphere in light bulbs so filament doesn’t burn

Question 28

use of mixtures

Answer 28

in gas lasers (barcode readers)

Question 29

how were noble gases discovered

Answer 29

density of nitrogen gas made in a chemical reaction was different to density of nitrogen obtained from air

Question 30

what is the group number

Answer 30

number of outer shell electrons

Question 31

what is period number

Answer 31

number of shells

Question 32

bonding in metals

Answer 32

atoms held together by metallic bonding - electrostatic attraction between cations and a sea of delocalised electrons

Question 33

bonding in non metals

Answer 33

molecules or giant structures held together by covalent bonds and a shared pair of electrons

Question 34

difference of transition metals

Answer 34

can form more than 1 type of ion - fe2+/fe3+
higher mp and bp
form coloured compounds and solution
most give coloured precipitates when reacted with NaOH

Question 35

coloured compounds in solution

Answer 35

fe2+ - green
fe3+ - yellow brown
cu2+ - blue
cr3+ - green