Studied by 0 peopleWho was the periodic table made by
Mendeleev
How did we know that Mendeleev’s table was correct
Because when we found new elements they fit into the periodic table just as Mendeleev predicted
How does the reactivity with water change as you go down the 1st group
The elements get more reactive
Why do the group 1 elements get more reactive down the group
Because the electrons are further away from the nucleus decreasing the gravitational energy making it easier to loose electrons
Why do group 1 metals react with water
Because they need to loose 1 electron to have a full outer shell and Oxygen need to gain 2 electrons to have a full outer shell
Symbol equation for lithium + water
2Li + 2H2O → 2LiOH + H2
Symbol equation for sodium + water
2Na + 2H2O →2NaOH + H2
Symbol equation for potassium + water
2K + 2H2O → 2KOH + H2
What happens to group 7 elements colour and state as you go down the group
They get darker and they move from gas → liquid → solid
Define diatomic elements
When 2 atoms covalently bond into a molecule
Which elements are diatomic
Hydrogen, Oxygen, Nitrogen and all of group 7
Why are group 7 elements diatomic
They react with each other to get a full outer shell
What is the pattern of reactivity down group 7
They get less reactive down the group
Describe the reaction between water and lithium
The lithium floats on the surface of the water
There is some effervescence
Describe the reaction between water and sodium
The sodium moves around the surface of the water at medium speeds
There is effervescence
Describe the reaction between water and potassium
The potassium moves around the surface of the water at high speeds
There is lots of effervescence
There is a small flame
Why did we not react water with any group 1 metals lower than potassium
They have very violent reactions which would be dangerous for students
Why do group 7 elements get less reactive down the group
Because the electron shells are further away from the nucleus, the attraction of the outer shell electrons decreases
What are the properties of group 1 elements
Low density
React with non metals to form +1 ionic bonds
White solids
Form colourless solutions
React with water and release hydrogen
Form hydroxides that dissolve in water to give alkaline solutions
Properties of the Nobel Gases
Unreactive because they have a full outer shell
All apart from He have 8 electrons in their outer shells
Boiling points increase with atomic mass
Properties of Group 7 elements
Non metals
Diatomic
Form -1 ionic bonds with metals
For compounds with non metals
Mass, melting point and boiling point increase with atomic mass
Reactivity decreases down the group
Properties of transition metals
High melting points
High density
Strong and hard
Less reactive
Form ions with different charges
Form coloured compounds
Are useful as catalysts
Note
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