Group 1 and Group 7 Flashcards
Why are lithium, sodium and potassium recognized as in the same group as a family of elements
Similar observations for reaction of water:
1. Fizzing
2. Metal floats and moves around on the water
3. Metal disappears
In each case a metal hydroxide solution is produced
These similarities provide evidence are in the same group of the Periodic Table (i.e. have the same number of valence elec.)
Differences between lithium, sodium and potassium and how this provides evidence for the trend in reactivity in Group 1
Lithium: Fizzing, floats and moves, disappears
Sodium: Fizzing, floats and moves, melts into a silver-coloured ball, disappears
Potassium: Fizzing, floats and moves, catch fire with a LILIAC flame, disappears
(each is more vigorous)
Therefore was we go down group 1, the elements become more reactive
Explain the trend in reactivity in Group 1 in terms of electronic configurations
As you go down the group, the valence electron is further from the nucleus, therefore there is a weaker force of attraction and it is more easily lost, and it is more reactive
Color and physical state of Chlorine (Cl2) at room temp.
Green, Gas + (should be handled in a fume cupboard as it is toxic, think of the Jews)
Color and physical state of Bromine (Br2) at room temp.
Red-brown, Liquid
Color and physical state of Iodine (I2) at room temp.
Grey, Solid
Explain the trend in reactivity in Group 7 in terms of electronic configurations
As you go down the group, the outer shell is further from the nucleus, therefore there is a weaker force of attraction between the nucleus and the electrons, making it harder to gain, and it is less reactive
Displacement reactions (e.g chlorine + potassium bromide)
-> potassium chloride + bromine
The more reactive halogen will displace a less reactive halogen
Group 7 elements are
diatomic
