Bonding 1 - Ionic

Question 1

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What is ionic bonding?

Answer 1

The electrostatic attraction between oppositely charged ions

Question 2

What affects the strength of an ionic bond?

Answer 2

• Smaller ionic radius and larger charge makes an ionic bond stronger

Question 3

How do ions form

Answer 3

positive cat(ions) form from losing electrons
negative an(ions) form from gaining electrons

Question 4

Reasons for the trends in ionic radii down a group

Answer 4

Ionic radii increases down a group:
* more shells so greater shielding and distance between nucleus and outer electrons, decreased attraction

Question 5

Reasons for the trends in ionic radii for a set of isoelectronic ions, e.g. N<sup>3-</sup> to Al<sup>3+</sup>

Answer 5

From N³⁻ to Al³⁺ ionic radius decreases:
* Increasing number of protons, greater attraction between nucleus and outer electrons
* Ions get smaller as electron cloud is pulled closer to the nucleus

Question 6

Physical properties of ionic compounds: melting points, conductivity, migration of ions

Answer 6

• high melting/boiling points, strong electrostatic forces between ions
• electrical conductivity when dissolved/molten

movement of ions:
* when electrical current supplied, ions migrate to oppositely charged electrodes

Question 7

Physical properties of ionic compounds: solubility in water

Answer 7

• The positive cation from the ionic solid is attracted to the negative end of the water molecules (oxygen)
• The negative anion from the ionic solid is attracted to the positive end of the water molecules (hydrogen)

Question 8

Why is water chosen as a solvent for ionic compounds?

Answer 8

Because it is a polar molecule, meaning different ends of the molecule are oppositely charged and can react with the oppositely charged ions in an ionic compound