Topic 2 - Bonding and Structure
Ionic Bonding
Define ionic bond
strong electrostatic forces of attraction between oppositely charged ions
What are ions?
charged particles that are formed when an atom loses or gains electrons
Describe the two main factors that affect the strength of ionic bonding
1. IONIC RADIUS - Smaller ions pack closer together, electrostatic attraction gets
weaker with distance, therefore small, closely packed ions have stronger ionic
bonding
2. IONIC CHARGE - greater the ionic charge, stronger the ionic bonding
Why are ionic compounds soluble in water?
water has polar bonds
H+ and OH- these charges are able to attract charged ions
Describe the physical properties of ionic compounds
high MP
do not conduct when solid
brittle - can't be shaped → repulsion between ions
often soluble in water but INSOLUBLE in non polar solvents → tells you
particles are charged
Describe the trend in ionic radius down a group
Ionic radius increases down a group
Because down the group the ions have more shells of electrons
Topic 2 - Bonding and Structure 1
, Thus, the outermost electron experiences less pull from positive nucleus
Draw the dot and cross diagram to show ionic bonding in MgO
What are isoelectronic ions?
Isoelectronic ions are ions of different atoms with the same number of electrons
Describe the ionic radius of a set of isoelectronic ions with increases atomic
number
ionic radius decreases of a set of isoelectronic ions as atomic number increases
Electrons stay the same but protons increases
This means electrons are attracted to the nucleus more strongly
What are molecular ions?
molecular ions are covalently bonded atoms that lose or gain an electron
Which electrons are lost when an atom becomes an ion?
electrons in the highest energy level
Topic 2 - Bonding and Structure 2