4A:Elements of Group 1 and 2 Flashcards
Give some properties of group 1 metals
Less dense than water
Low melting points
Soft
How does ionisation energy change going down group 2 and why?
Decreases
Every element has an extra electron shell
More shielding occurs, distance from the nucleus increases, and effective nuclear charge doesn’t change
How does melting temperature change going down group 2 and why?
Decreases
Charge density decreases as you do down the group so less energy needed to overcome electrostatic attraction
How does atomic and ionic radii change going down group 1 & 2 and why?
Increases
Number of orbitals increases going down the group
What is the first ionisation energy of group 2 metals in comparison to group 1 metals?
Group 2 metals have larger first ionisation energy
As they have an increased nuclear charge but decreased radii
What is the melting points of group 2 metals in comparison to group 1 metals?
Higher melting points
As they lose 2 electrons per atom for metallic bonding therefore it is stronger
What is the electrical conductivity of group 2 metals in comparison to group 1 metals?
Better electrical conductivity
What is the hardness of group 2 metals in comparison to group 1 metals?
Harder than group 1 metals
What is the oxidation number of group 1 and 2 ions?
+1 : Group 1
+2 : Group 2
What are group 1 and 2 metals usually in redox reactions?
Reducing agents
What happens when group 2 metals react with water?
Metal hydroxides (aq) and hydrogen are formed M + 2H2O -> M(OH)2 + H2
How does the reactivity of the group 1 and 2 metals change as you go down?
They get more reactive (outer electron more easily lost)
What happens when group 2 metals react with oxygen?
Burn brightly in air (except beryllium) to form white solids
2M + O2 -> 2MO
What happens when group 2 metals react with chlorine?
Solid white chlorides form (except beryllium which forms a covalent anhydrous chloride)
M + Cl2 -> MCl2
How reactive are group 2 metals in relation to group 1?
Less reactive as group 1 only need to lose 1 electron
Why must Mg and Ca be reacted with steam in order to form their metal oxides?
They are not as reactive as the other group 2 metals
In cold water they form their metal hydroxides instead
What are the oxides and hydroxides of group 2?
Bases (will react with water to form OH- ions
What is the exception to the group 2 oxide bases?
Beryllium oxide - doesn’t react with water & hydroxide is insoluble
Magnesium oxide - reacts slowly & hydroxide isn’t very soluble