8 - The Periodic Table Flashcards
What are the properties of Group 1/Alkali Metals?
- Relatively soft
- Reactive shiny surface tarnished if exposed to air
- React with air and water
- Relatively low densities
- Relatively low melting points
- Conductive
What are the trends that involve Group 1 metals as you go down the group?
- Decreasing melting point
- Increasing density
- Increasing reactivity
What happens when Lithium reacts with water?
It will remain on the surface and move around, leaving effervescence. It will leave an alkaline solution.
It may burn and create a red flame
What happens when Sodium reacts with water?
It will remain on the surface and move around more vigorously than Lithium, leaving effervescence. It will leave an alkaline solution. The heat causes the metal to melt and form a small ball.
It may burn and create a yellow flame
What happens when Potassium reacts with water?
It will jump around, burning the hydrogen that is formed in the reaction to form a lilac flame. A pop/splutter may be heard at the end of the reaction. It will leave an alkaline solution. The heat causes the metal to melt and form a small ball.
What is the general formula for Alkaline metals reacting with water?
2M(s) + 2H20(l) –> 2MOH(aq) +H2(g)
M = Alkali metal
Why does reactivity increase as particles move down group 1?
The electron in the outer shell is farther away for the nucleus each time, meaning the electrostatic attraction is weaker and it is easier for the atom to lose it and react to form a full outer shell.
Why does density increase as particles move down group 1?
The nucleus gets bigger, meaning there are more protons and neutrons
Why does melting point decrease as particles move down group 1?
As the ions get larger the distance between the bonding electrons and the positive nucleus gets larger and reduces the overall attraction between the two.
In the reaction of Alkali metals with water, which is oxidised and which is reduced, and why?
The metal is oxidised, as it loses electrons to become a metal hydroxide.
The water is reduced, as the hydrogen gains electrons, separating itself from other oxygen and hydrogen ions.
What do halogens undergo displacement reactions with?
Halide Ions
Name the halogens in order of reactivity from most to least reactive
(That we need to know)
Chlorine
Bromine
Iodine
Def. Spectator ion
An ion that does not gain or lose electrons during a reaction, so it does not prticipate in the reaction
Def. Displacement reaction
A reaction where a more reactive element reacts with an ion of a less reactive element
Wha are the five properties of transition metals?
- Vey high melting point
- Very high density
- For coloured compounds
- Form ions with variable oxidation numbers
- Act as catalysts for chemical reactions
