Ionisation Energy

Based on the position of calcium & copper in the periodic table, make comparisons with respect to their:– Atomic radius – ionisation energy– Metallic character– Order in the Activity Series (more likely to oxidize)

– Extraction method for each– Possible experiment(s) that will help to compare

their reactivity

Problem #1

• Avoid personification

“…because he has a larger nucleus….”

Problem #2

• Stating the obvious

“…both elements differ in their radius and number of protons….”

Problem #3

• Positions don’t mean anything!

“…because it is above, it is more reactive….”

The apple must be more reactive, it is found above. I am found

below, therefore, I must be less reactive

Problem #4

• Cause and Effect

“…because it is on the ‘left’, it is more reactive”

versus

“…because it is more reactive, it is on the left”

Problem #5

• Extraction with Carbon or CO

Used for metals that are slightly more reactive than copper.

Problem #6

• Froth floatation & electrolysis of Cu

These are not methods of extraction; these points are irrelevant

(floatation is to mechanically separate Cu; electrolysis is to purify it in the very end)

Atomic Radius

• Atomic radii decrease across a period as each subsequent element gains an additional proton, creating a greater attraction to its valence shell.

• Ca, having less protons than copper, has a weaker attraction for its outer electrons.

• This results in Ca having a weaker nuclear attraction and a larger radius than that of Cu

Ionisation Energy

• Ionisation energy is the energy required to remove an electron from an atom

• Since Ca has a larger radius, it requires less energy to remove the valence electron as it is further away from the oppositely charged nucleus

• Cu, having a smaller radius, exerts a greater attraction for is electrons that are closer to the nucleus. This makes it difficult to remove the attracted electron which makes the I.E. greater for Cu

Metallic Character

• Metals in Group 2 will readily lose their valence electrons to achieve noble gas configurations due to its larger atomic radii and lower ionisation energies

• The ease to which is loses electrons makes Ca more metallic in character in comparison to Cu which doesn’t readily lose its electron

Activity Series

• When comparing the reactivity series of metals, Ca, with the lower ionisation energy, will readily lose its electron making it more reactive compared to Cu

• Therefore, Ca will readily oxidize to form an ion compared to Cu

ExperimentsMetal Air water Weak acid

Calcium Burns & turns white Reacts to produce H2 gas and hydroxide

Reacts to produce H2 gas

Copper No change No change No change

React each metal with each other’s metal ion, as follows:

Ca (s) + Cu+2 (aq) Ca+2 (aq) + Cu (s)

Cu (s) + Ca+2 (aq) No REACTION (copper is not reactive enough to displace Calcium ions in solution)