alakline

Question 1

give two observations when lithium reacts with water

Answer 1

bubbles
get smaller and dissappear
floats

Question 2

give two observations when pottasium reacts with water

Answer 2

catches fire
floats on water
bubbles

Question 3

explain why lithium is less reactive than pottasium
refer to atomic structure

Answer 3

li has a smaller atomic radium
so valence electron is attracted strongly to nucleus
cant be easily lost as k

Question 4

give observatio would be different if k used instead of li

Answer 4

burn with a flame
reacts more vigrous
form a ball

Question 5

identify the most reactive metallic element in the periodic table

Answer 5

francium

Question 6

the elements in group 1 show a clear trend in some of the phisical proprities
identify the phisical property that shows a clear trend

Answer 6

melting point

Question 7

when a peice of lithium is removed from the oil dried and cut the exposed surface

Answer 7

changes from shiny to dull

Question 8

why lithium and sodium have simillar reactions with water

Answer 8

they have one electron in their valence shell

Question 9

is melting point decrease or increase down group of alkaline metal

Answer 9

decrease

Question 10

is denisty increase and decrease down group

Answer 10

increase

Question 11

phisical properties of alkali metals

Answer 11

they have shiny silvery surface when freshely cut with a knife
they are soft metals
have low densties
they are good conductor of electricity and heat
they have low melting point

Question 12

give me melting point of lithium

Answer 12

180

Question 13

give me melting point of pottasium

Answer 13

64

Question 14

why pottasium floats on water

Answer 14

as its less dense than waTER

Question 15

WHAT IS THE lightest alkali metal

Answer 15

lithium

Question 16

why they are called alkali metals

Answer 16

as they react with water forming alkaline solution

Question 17

why reactivity of alkali metal increase on descending group

Answer 17

as number of shells increase so distance between the valence electron and nucleus increases thus the valence electron is less firmly held to the nucleus and cant be lost easily

Question 18

sources of sodium chloride

Answer 18

sea water,ground rock salt deposits

Question 19

where metals are stored

Answer 19

store under oil /keresone

Question 20

why metals are store under keresoine

Answer 20

to isolate them from air and water

Question 21

observation when alkali react with oxygen

Answer 21

give a white oxide layer

Question 22

difference of li and k and na

Answer 22

lithium doesnt give a flame
na gives yellow flame
k gives a lilac flame

Question 23

why reaction is more violent in case of patossium than in case of sodium

Answer 23

pottasium is more active than sodium

Question 24

example of chemical equation alkali metal reacts with water

Answer 24

2li+2h2o=2lioh

+h2

Question 25

reaction alkalis with air

Answer 25

4na+o2=2na2o

Question 26

reaction alkali with halogen

Answer 26

2na+cl2=2nacl

Question 27

uses of sodium

Answer 27

used in extraction of titanium

Question 28

Uses of tatinum

Answer 28

Make body of rockets

Question 29

Chemical equation of extraction of titanium

Answer 29

Ticl3+3Na=>Ti +3Nacl

Question 30

What is meant by reactivity of metals

Answer 30

Tendency to lose it’s valence electron

Question 31

Observe li when put in cold water

Answer 31

Gas fizzes around it,float,metal chamge into ball and get smaller and disappear

Question 32

Observation when k put in cold wayer

Answer 32

React violently,melt immediately, catch fire with lilac flame,floats,change into ball and get smaller and disappear in water