Ionic and Covalent Bonding Flashcards
When are ions formed?
When electrons are transferred from one atom to another. The simplest ions are single atoms which have either lost or gained 1, 2 or 3 electrons so they’ve got a full outer shell.
What ions do group 1 elements form?
1+
What ions do group 2 elements form?
2+
What ions do group 6 elements form?
2-
What ions do group 7 elements form?
1-
What are the compound ions I need to know?
Nitrate…NO3-
Carbonate…CO3 2-
Sulfate…SO4 2-
Ammonium…NH4+
What does an electrostatic attraction do?
It holds positive and negative ions together- its very strong.
When atoms are held together like this, its called ionic bonding.
What is an ionic bond?
An electrostatic attraction between two oppositely charged ions.
What do you get when oppositely charged ions form an ionic bond?
An ionic compound.
What are ionic crystals?
Giant lattices of ions.
What is a giant lattice?
A lattice is just a regular structure. The structure’s called giat because it’s made up of the same basic unit repeated over and over again.
What three physical properties can the structure of ionic compounds determine?
Electrical conductivity
Melting and boiling points
Solubility
What features of an ionic compound determines electrical conductivity?
Ionic compounds conduct electricity when they’re molten or dissolved- not when they’re solid.
The ions in a liquid are free to move (and they carry charge).
In a solid they’re fixed in position by the strong ionic bonds.
What features of an ionic compound determines melting and boiling points?
Ionic compounds have high melting and boiling points.
The giant ionic lattices are held together by strong electrostatic forces.
It takes loads of energy to overcome these forces, so melting and boiling points are very high.
What features of an ionic compound determines solubility?
Ionic compounds tend to dissolves in water.
Water molecules are polar- part of the molecule has a small negative charge, and the other bits have small positive charges.
The water molecules pull the ions away from the lattice and cause it to dissolve.