Ride the Storm: Navigating Through Unstable Periods / Katerina Rudko (Belka G...
Atoms, Elements, Compounds, Mixtures, GLS.pptx
1. Solid, Liquid or Gas?
You need to
remember which
of the first 20
elements are
gasses, and which
are liquids
2. Compounds and Mixtures
• All substances are either elements, compounds or
mixtures.
• An element is made up of only one type of atom.
Carbon and oxygen are both elements.
• A compound is a substance made up of two or more
elements joined together. For example, when carbon
atoms join with 2 oxygen atoms, they form a
compound called carbon dioxide.
• Carbon atoms that are just mixed with oxygen atoms,
but are not attached to them, form a mixture. A
mixture can also contain compounds, if they are not
joined to the other substances in the mixture.
• For example, air is a mixture of elements such as
nitrogen and oxygen, and compounds, such as water
and carbon dioxide.
3. “Stable”
atoms/elements?
Atoms are more stable energetically when
they have eight electrons in their valence
shell, the outermost electron shell.
Atoms ‘want’ a full outer shell of electrons,
i.e. they are most stable with a full outer shell.
This explains why the Group 8 elements, the
noble gases, do not react to make compounds
— they are already as stable as they can be