atomic structure Flashcards
Atoms of different elements can be combined together to create what?
Compounds
What are elements?
a substance that cannot be broken down into any other substance
there are 118 on the periodic table
What are atoms?
the smallest piece of an element that can exist
What are compounds?
A chemical bonding of atoms from at least 2 different elements
What is the chemical formula for sodium oxide?
Na₂O
What are the key features of a chemical reaction?
Compounds are broken up or formed
At least 1 new substance is created
No atoms are created or destroyed
Measurable energy change
A chemical equation shows what happens in a chemical reaction using symbols or words.
What does an equation look like?
The reactants (chemicals that are reacting) are on the left
The products (chemicals that are made) are on the right
4Na + O₂ –> 2Na₂O
What are mixtures?
2+ substances (elements or compounds) that haven’t been combined chemically, jumbled up.
They can be separated as their is no bonding between the substances
Name 2 separation techniques for mixtures
Filtration
Crystallisation
Chromatography
Distillation
What is Chromatography used to separate?
Solutions with a number of different solutes (dissolved solids) in a solvent
What is distillation?
A special technique used to separate a mixtures of liquids
Separates liquids with different boiling points
Name two of the most common gases found in air.
Nitrogen
Oxygen
Carbon dioxide
Solute vs solvent vs solution - connect them
Solution The liquid in which a solid dissolves
Solvent Dissolved solid
Solute A liquid that contains a dissolved solid
Solution A liquid that contains a dissolved solid
Solvent The liquid in which a solid dissolves
Solute Dissolved solid
What was JJ Thompsons model of the atom?
The plum pudding model - a clump of positive charge with electrons randomly scattered in it
What was Rutherford’s model of the atom?
Earnest Rutherford discovered that alpha particles bounced back when fired towards the atom
He concluded that an atoms mass is concentrated in a positively charged nucleus the centre of it
