C1 - Compounds Flashcards
What is a compound?
A compound is a substance formed from two or more elements,the atoms of each are in fixed proportions throughout the compound and they are held together by chemical bonds
What do making bonds involve?
This involved atoms giving away,taking or sharing electrons. ONLY the electrons are involved - the nuclei of the arent affected at all when a bond is made
How can you separate the original elements of a compound?
A chemical reaction is needed
What does a metal and non-metal consist of when they make a compound?
They consist of ions.The metal atoms LOSE electrons to form positive ions and the non-metal atoms GAIN electrons to form negative ions
What is ionic bonding?
The opposite charges(positive and negative) of the ions mean that they are strongly attracted to each other.
(Examples of compounds which are bonded ionically include Sodium chloride, magnesium oxide and calcium oxide)
What is covalent bonding?
A compound formed from non-metals consists of molecules.Each atom shares an electron with another atom.
(Examples include hydrogen chloride gas,carbon monoxide and water)
Are the properties the same in a compound compared to the elements in it?
No,they are usually totally different from the properties of the original elements.
(For example if iron and sulfur were to react,the compound formed known as iron sulfide is a dull grey solid lump which doesnt behave anything like either iron or sulfur)
How can compounds be presented?
By formulas.The formulas are made up of elemental symbols in the same proportions that the elements can be found in the compound
(For example CO2 is a compound formed from a chemical reaction between carbon and oxygen containing 1 carbon atom and 2 oxygen atoms)
Examples of formulas (DONT NEED TO REMEMBER JUST READ IT)
- Carbon dioxide (CO2)
- Ammonia (NH3)
- Water (H2O)
- Sodium chloride (NaCl)
- Carbon monoxide (CO)
- Hydrochloric acid (HCl)
- Calcium chloride (CaCl2)
- Sodium carbonate (Na2CO3)
- Sulfuric acid (H2SO4)
