2 - Group 2, the alkaline earth metals Flashcards
In order, what are the group 2 elements?
Be, Mg, Ca, Sr, Ba, Ra
Are group 2 metals oxidised or reduced?
Oxidised as they lose electrons when they react
Oxidation state 0 → +2
What is the general trend in atomic radius down group 2?
Atomic radius increases
Why does atomic radius increase down group 2?
Down the group, the atoms have more shells of electrons making the atom bigger
What is the general trend in 1st ionisation energy down group 2?
1st IE decreases down group 2
Why do 1st ionisation energies decrease down group 2?
- Weaker forces of attraction between nucleus and outermost electrons
- Shielding increases
What is the general trend in melting points down group 2?
Melting point decreases
Why do melting points decrease down group 2?
- Metallic bonding weakens as atomic size increases
- Distance between positive ions and delocalised electrons increases so electrostatic forces between them weaken
Why does Mg have a lower melting point than Ca?
Mg’s crystal structure changes
What is the trend in reactivity down group 2?
Reactivity increases
Going down the group, why are group 2 elements more reactive?
Outer electrons are easier to lose
- Due to increase in atomic radii and shielding
When group 2 elements are reacted with oxygen, what is formed?
Metal oxides
When group 2 elements are reacted with water, what is formed?
Metal hydroxide & hydrogen
Describe the reaction of group 2 elements with water
- Group 2 metals react with water in a redox reaction
- Metals oxidise 2+
- Metal hydroxides forms as an alkaline solution
What is the general equation for when group 2 elements react with water?
Metal + water → metal hydroxide + hydrogen