Trends in the Group 2 Elements

Question 1

what is the definition of first ionisation energy

Answer 1

• the amount of energy required to remove one electron from each atom
• in one mole of atoms in there gaseous state

Question 2

because these are group 2 elements, what would the general equation for the second ionisation of them look like, using M

Answer 2

M+(g) = M2+(g) + e-

Question 3

what is the trend on the ionic radii of the elements down group 2 and why

Answer 3

• they increase
• as the number of electrons each one has increases
• they have one more shell of electrons than the prior

Question 4

what is the trend in the 1st and 2nd ionisation energies of the group 2 elements down the group and why

Answer 4

• they decrease
• the electrostatic attraction between the outer electrons and the nucleus becomes weaker
• as they get further away from each other as more shells are added
• the shielding effect is also increased as you go down because of this

Question 5

what are the three factors to consider when explaining trends in ionisation energies

Answer 5

• nuclear charge
• atomic radius
• shielding effect

Question 6

what is a factor that does against the trend in ionisation energies down group 7

Answer 6

• the nuclear charge
• it increases as you go down the group
• so the electrostatic attraction in this sense is increased
• but it isnt significant enough to change the trend

Question 7

what is the general trend in reactivity down group 2

Answer 7

the reactivity of the elements increase

Question 8

using the knowledge of their trend in ionisation energies, why does their reactivity increase

Answer 8

• there is a decrease in the ionisation energies down the group
• meaning that less energy is required to remove the two electrons in the outer shell
• in other words the electrons are more readily to be given up as you go down