Atomic Structure Flashcards
What are all substances made out of
atoms
Substances made up of one type of atom
elements
What does the staircase on the periodic table represent?
From Boron to the right
Dividing line between metals and non-metals
Substances made up of different types of atoms bonded together
Compounds
What is an atom
Nucleus containing protons and neutrons
Surrounded by electrons in fixed positions in a shell
Where are the reactants and products of an equation?
left = reactants right = products
Mass equal on both sides
Compare compounds and mixtures
Compounds:
Fixed composition
Separate the elements in a compound
Chemical bonds between atoms of different elements in the compound
Mixtures:
No fixed composition
Separate again more easily by physical means
No chemical bonds
Crystallisation
1) Weigh oxide or carbonate using a 2 d.p balance
2) Measure out acid in a measuring cylinder
3) Mix in a beaker and stir to make it react
4) Filter off excess solid using funnel and filter paper
5) Add filtrate (liquid) to an evaporating basin and heat until salt begins to form
6) Turn Bunsen off
7) Let water evaporate leaving salt crystals behind
8) Dry with paper towel
Fractional Distillation
Separates mixtures of miscible liquids (liquids that dissolve in each other)
Miscible liquids have different boiling points
Vapours pass over and between glass beads in the fractionating column before they reach condenser
Higher boiling point will condense more readily on the cooler glass beads nearer the bottom of the column and drip back down into the flask beneath
Lower boiling point continues rising over condenser
Thomson
Plum pudding model
Discovered electrons
Thought electrons were in cloud of positive charge
Rutherford
Gold foil
Discovered nucleus
Electrons must orbit around nucleus, containing positively charged protons
Bohr
Discovered electrons orbit at fixed positions in shells
Chadwick
Discovered atom we use today
Neutrons have no charge with same mass as a proton
Charge and mass of proton and how to figure it out
+1 charge (positive)
1 = mass
Bottom number of atom e.g. Oxygen = 8
Charge and mass or neutron
0 charge (no charge) 1 = mass
Two numbers taken away e.g. Oxygen = 16-8 = 8
