Group 2, the alkaline earth metals Flashcards
What are the Group 2 elements sometimes called, and why are they called this?
Which block of the periodic table do Group 2 elements belong to?
The Group 2 elements are sometimes called, alkaline earth metals. This is because their oxides and hydroxides are alkaline
The s - block
How do Group 2 elements compare to Group 1 elements in terms of reactivity?
Group 2 elements are less reactive than Group 1 elements
Why is beryllium not considered typical of Group 2?
It has unique properties and is not considered in Group 2 trends
What happens to the outer s - orbital as you go down Group 2?
How does atomic size change going down Group 2?
They become further away from the nucleus
Atoms get bigger
Why do Group 2 atomic radii increase down the group?
Each element has an extra filled main level of electrons compared to the one above it
Why do Group 2 elements have high melting points?
They have a giant metallic structure with strong metallic bonds
What happens to the melting points of Group 2 elements as you down the group?
They decrease slightly from calcium downward
Why do melting points decrease down Group 2?
As you go down Group 2, the delocalised electrons become further from the positive nuclei, weakening the metallic bonds
Which Group 2 element does not fit the melting point trend?
Magnesium, which has no simple explanation for this anomaly
What happens to Group 2 atoms in chemical reactions?
They lose two outer electrons to form +2 ions
How much energy is required for the complete ionisation of a Group 2 atom?
The sum of the first and second ionisation energies
What happens to the first and second ionisation energies as you go down Group 2, and why?
> The ionisation energies decrease because the group 2 elements become bigger, providing more shielding.
> Therefore there is a weaker attraction between the nucleus and the outer electrons and so the outer electrons are more and more easily lost.
What is the trend in reactivity of Group 2 metals with water?
The reactivity increases down the group
What is observed when calcium reacts with water?
What is the equation formed when calcium reacts with water?
Calcium fizzes in the water and after a time, forms a white solid {Ca(OH)2}, which is a slightly soluble solid in water
Ca + 2H2O ⇒ Ca(OH)2 + H2
What is observed when magnesium reacts with a) cold water, b) steam?
What is the equation formed when magnesium slowly reacts with cold water?
What is the equation formed when magnesium rapidly reacts with stream?
Magnesium reacts very slowly with cold water but rapidly with steam
Reaction with cold water: Mg + 2H2O ⇒ Mg(OH)2 + H2
Reaction with steam: Mg + H2O ⇒ MgO + H2
What is observed when strontium reacts with water?
What is the equation formed when strontium reacts with water?
Strontium fizzes in water and forms a colourless solution
Sr + 2H2O ⇒ Sr(OH)2 + H2
What is observed when barium reacts with water?
What is the equation formed when barium reacts with water?
Barium fizzes in water and forms a colourless solution
Ba + 2H2O ⇒ Ba(OH)2 + H2
