EDEXCEL CHEMISTRY ADDITIONAL C2 BONDING
- Created by: caitlinford74
- Created on: 26-04-16 18:46
Bonding
Compound: Two or more atoms chemically bonded together
Anion: a negative ion that has gained electrons (usually non-metals)
Cation: a positive ion that has lost electrons (usually metals)
Ionic Bonding
Ionic bonding is when positive and negative ions are held together by electrostatic attraction.
Ionic bonding is between a metal and a non-metal. Ionic bonding (likewise with all bonding) occurs because the element wants a full outer shell - to become stabilised. When drawing ionic bonding, we draw the shared electron on the non-metal that wanted to gain an electron, but no electrons (obviously) are drawn on the metal that wanted to lose an electron, however the electron it wanted to lose has vanished because it shared it with the non-metal. We draw brackets [ ] around the ion and write its new charge in the top right.
We name ionic compounds according to the ions it contains. For example, if the negative ion (the ion that wanted to gain electrons, the non-metal) is an element, the name ends in -ide.
e.g potassium bromide
If the negtaive ion is a compound containing oxygen th suffix changes to -ate.
e.g magnesium carbonate
Ionic substances are good conductors of electricity when in aqueous solutions or when molten. However, it is not the electrons that carry the charge in this instance, it is the ions theirselves. Ionic substances are also soluble in water, with high boiling and melting point because of the strong electrostatic forces.
Metallic Bonding
Metallic bonding is the bonding between two metals.
In metallic bonding, the boiling and melting point are very high because it takes a lot of force to break the electrostatic bonds between the positive metal ions and the sea of delocalised electrons. The positive metal ions and sea of delocalised electrons are attracted to eachother because opposites attract. The metal atoms theirselves are held together by strong bonds as the sea of delocalised electrons aren't associated to any one atom, so they move freely keeping the atom together - henceforth, a large amount of energy is needed to break these…
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