alkali metals

Question 1

3 physical properties (differ from normal metals)

Answer 1

1- soft
2- low density (weigh less)
3- low metal and boiling points

Question 2

what makes this group special

Answer 2

they are more reactive than other groups

Question 3

in which direction does the reactivity increase

Answer 3

from top to bottom (down the group)

Question 4

in which direction does the melting and boiling point increase

Answer 4

bottom to top (up the group)

Question 5

what group are they

Answer 5

group 1

Question 6

how many valence electrons do they have

Answer 6

grp no= no of valence electrons = 1

Question 7

what are valence electrons

Answer 7

electrons found in the outermost shell of an atom

Question 8

why are alkali metals in group 1 so reactive

Answer 8

all atoms want to have a full outermost shell to be stable, alkali metal have only one valence electron (electron in outermost shell). lower the no of valence electrons= easier to lose electrons, the easier it is to lose electrons= more reactive (reactivity incre)

Question 9

what makes a substance reactive

Answer 9

how easy it is for it to lose valence electrons

Question 10

what are the 2 things affect the reactivity of a substance

Answer 10

1- no of valence electrons it has (no of electrons in outermost shell):

• > lower no of valence electrons= easier to lose them = more reactive. (uses less energy to lose them then to gain more to make 8 electrons in outermost shell)
• > higher no of valence electrons= harder to lose them but easier to gain = less reactive

-no of valence electrons= grp no

2- no of shells :
- positive nucleus holds valence electrons in place, if there are more total electrons in atom, the no of shells to hold them incre and this incre the distance betw the nucleus and the outermost shell, weakens the attractive force = making it easier to lose electrons in outermost shell.

• shell no increases and u go down the grp so the period/
• > higher total no of elctrons= more shells= weaker forces= easier to lose valence electrons= more reactive

Question 11

what type of ion does metals form when they react

Answer 11

they form positive ions (cations) because they lose electrons easier due to the low no of valence electrons (grp no lower than non metals)

Question 12

what type of ion does non metals form when they react

Answer 12

they don’t form ions or negative ions (anions) , because its easier to gain ions than lose ions (high no of valence electrons)

Question 13

what kind of compound does alkali metals (grp1) form when they react with non metals

Answer 13

ionic compound: metal donates one electron to a non-metal,

• so they both have full outermost shells,
• this gives the elements opposite charges and they are therefore attracted to each other, this attraction is called an ionic bond

Question 14

what do ionic compounds form when they dissolve in water

Answer 14

colourless solutions

Question 15

what does alkali metals (group1) and water (H2O) form

Answer 15

they form metal hydroxide + hydrogen gas

Question 16

how do alkali metals (grp 1) and water react

Answer 16

they react vigorously

Question 17

what does alkali metals (grp1) and chlorine (Cl) form

Answer 17

they form metal chloride salts

Question 18

how do alkali metals (grp 1) and chlorine (Cl) react

Answer 18

they react vigorously

Question 19

what do alkali metals (grp1) and oxygen form

Answer 19

they form metal oxides, the type of metal oxide depends on the metal

Question 20

what do Li + O2 form

Answer 20

Lithium oxide (Li2O)

Question 21

what do Na + O2 form (tip: there are 2)

Answer 21

sodium oxide (Na2O)

or

sodium peroxide ( Na2O2)

Question 22

what do K + O2 form (tip: there are two)

Answer 22

potassium peroxide (K2O2)

or

potassium superoxide (KO2)