FC13 Flashcards
(7 cards)
How are the electronic configuration a trend in group 2
The elements in the same group all have the same number of electrons in the outer shell
They all have s2 as their last configuration
Why does the size increase down group 2
Extra shells of electrons are being added at increasing from the nucleus. The distance is further increased by greater shielding from inner shells and thus outweighs the increasing nuclear charge, so the electrons are attracted less strongly and can be further from the nucleus.
Why does the ionisation energy decrease down group 2
More shells of electrons are being added so outer electrons experience more shielding and are further from the nucleus because of the increasing atomic radius. These 2 factors outweigh the increasing nuclear charge so the attraction to the nucleus decreases.
Why does the reactivity increase down group 2
The decreasing first and second ionisation energies explain why the reactivity of the elements increases on going down the group. Elements need to be ionised to react and form compounds which means decreasing ionisation energies mean decreasing activation energies and hence faster reactions
What happens when group 2 elements react with oxygen
The elements burn vigorously in oxygen. My burns with a very bright white light and turns into a white powder, magnesium oxide
The reactions become more vigorous on going down the group as the ionisation energies of the elements decrease and they consequently react more readily.
What happens when group 2 elements react with water
Calcium metal reacts vigorously with water, forming hydrogen gas and an alkaline solution of calcium hydroxide.
Ca(OH)2 is only slightly soluble in water .
Mg reacts similarly but very slowly in cold water. The reactivity of the elements with water increases down the group, calcium reacts vigorously and barium reacts explosively
What happens when group 2 elements fact with acids
They react with dilute acids to form hydrogen and solution of the corresponding salt
