All pupils will be able to Baseline Describe how properties of the elements in Group 1 depend on the outer shell of electrons of the atoms Most pupils will be able to Further Explain how properties of the elements in Group 1 depend on the outer shell of electrons of the atoms ID: 558276
Download Presentation The PPT/PDF document "What are the properties and trends of Gr..." is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
What are the properties and trends of Group 1 elements?
All pupils will be able to (Baseline):
Describe how properties of the elements in Group 1 depend on the outer shell of electrons of the atoms.
Most pupils will be able to (Further):
Explain how properties of the elements in Group 1 depend on the outer shell of electrons of the atoms.
Some pupils will be able to (Challenge):
Predict properties from given trends down the group.Slide2
Your Task as you watch:
You will need to fill in your sheet with the information that we discover as we see the alkali metals demonstration.
We will discuss the equations section at the end.
You will need to predict what the reaction for
Rb
would be using this data.Slide3
Equations:
Lithium
What were your reactants?
What were the products formed?
Fill in the equation with what we know:
Lithium
(s) + Water(l) Hydrogen(g) +
?Slide4
Symbol Equation: Lithium
Lithium
(s)
+ Water
(l)
Hydrogen
(g) +
?
Li
(s)
+ H
2
O
(l) H2(g) + LiOH(aq)
2
2
2
Now complete the equations for the other Alkali MetalsSlide5
Rubidium
Physical Properties:
Very soft, relatively low melting point, shiny when cut.
Reactivity with water?
Very vigorous
Products formed?Hydrogen gas and Rubidium HydroxideWord Equation (Reaction of Rubidium and water)
Rubidium(s) + Water(l) Hydrogen(g) + Rubidium Hydroxide (aq)Symbol Equation (Reaction of Rubidium and water)2Rb + 2H2O 2H2 + 2RbOHSlide6
https://www.youtube.com/watch?v=m55kgyApYrY
Rb
, Cs
braniac science (warning: it says ‘the dogs nuts’ in it)Alkali metals in water, accurate! (2:21min) Use this if not doing the demo. Episodes:
Group 1 as an example of Groups in the periodic table (2:30 min) Trends in periodic tableSlide7
Discovering this allowed us to explain some of the properties in Group 1.
The Patterns in the Periodic Table
What are the patterns in the Alkali Metals?
Li
Na
K
Rb
Cs
Fr
Reactivity Increases
Melting and Boiling Point Decreases
Size of the atom increasesSlide8
The alkali metals have one too many electrons – they want to get rid of the one on the outer shell
Reactivity
The electron is kept here because the nucleus in the middle has a large positive charge and attracts it inSlide9
Distance
As you move down Group 1 the distance the electron the metal wants to get
rid
of
is away from the big positive – the source of its attraction - gets further ….the attraction fades
Li
Na
K
Rb
Cs
Fr
A
T
T
R
A
C
T
I
O
N
What is happening to the size of the atom here?Slide10
Shielding
The electron is attracted to the nucleus as it has an opposite charge.
However, if there are electrons on inner shells then these “shield” the outer electrons from the positive charge of the nucleus.
This means that the outer electrons attraction to the nucleus is even lower the more shells there are.Slide11
What does this mean for reactivity?
Li
Na
K
Rb
Cs
The easier an electron leaves the more reactive the metal is!!
Very Slow
Slow
Medium
Fast
Very FastSlide12
Past Exam Question
(
1)
These
are the electronic structures of the atoms of three different elements.2.8.1 2.8.8 2.8.8.1element A
element B element C(a) Identify elements A and B. Element A is ............................... Element B is ...............................(b) (i
) Why is element C more reactive than element A?
(
ii) Why is element B unreactive?Slide13
Answers
1
.
(
a) A is sodium/Na* B is argon/Ar*
each for 1 mark(*case of letters must be correct)(b) (i) • outer electron (in element C / 2.8.8.1 / potassium) is at ahigher energy level / in a more outer shell/further away from nucleus / shielded by more full electron shells• electron is more easily lost/less strongly held / attracted
each for 1 mark(ii) • (element B / 2.8.8 / argon) has an outer shell that
is complete/has
8 electrons
• no tendency to gain or lose electrons / has a stable
configuration• (not ‘is stable’ / ‘in group O’ / ‘a noble gas’)
each for 1 mark[6]