Topic 1 Flashcards
(25 cards)
What charge do protons, neutrons and electrons have?
Protons: positive
Neutrons: no charge
Electrons: negative
What is an element?
A substance made up of atoms that all have the same number of protons in their nucleus.
What is an isotope?
Different forms of the same element, with the same number of protons, different number of electrons.
What is a compound?
Substances formed from two or more elements, held together by chemical bonds, they have different properties compared to the original elements.
The metal atoms [?] electrons to form [?] ions. Non-metals [?] electrons to form [?] ions? What is this called?
Lose, positive, gain, negative.
Ionic bonding
What is covalent bonding? Is this for metals or non-metals only?
Bonds by sharing an electron. Non-metals only.
Equation for relative atomic mass?
Ar = sum of (isotope abundance (%) * isotope mass number) / sum of abundances of all the isotopes (%)
Who was John Dalton and what did he describe an atom as?
A scientist who said atoms were solid spheres made up of elements.
Who contradicted John Dalton’s idea, what year and what did he suggest?
1897 - J.J Thomson. Found that atoms must contain electrons. He created the plum pudding model.
Who created the Alpha particle scattering experiment, what year, what did they find?
1909 - Ernest Rutherford. Used a thin sheet of gold foil and found that the atom must contain a nucleus.
What did Niel Bohr find?
He created Bohr’s Nuclear Model. He found that atoms contained shells.
What happened 20 years later?
James Chadwick discovered neutrons. Created the closest nuclear model to the current modern day one.
Who was Dmitri Mendeleev, what did his periodic table look like, what year, how did he group the elements?
1869 - Left gaps and predicted elements. He grouped them based on similar properties and atomic weight.
How are elements on the periodic table laid out now?
Groups of similar properties, in order of increasing atomic (proton) number.
What is a mixture?
2 or more elements or compounds mixed together with no chemical bond.
What is chromatography used for?
Separate compounds out of a mixture.
PRACTICAL: Evaporation (soluble from solution)
- Pour solution into an evaporating dish.
- Slowly heat solution.
- Solvent will evaporate, solution becomes more concentrated.
- Crystals will form.
- Keep heating until the crystals are dry.
PRACTICAL: Crystallisation (soluble from solutions)
- Pour solution into an evaporating dish.
- Heat, once evaporated remove the dish and leave to cool.
- Crystals will form in a cold, concentrated solution.
- Leave crystals in a warm place to dry.
PRACTICAL: Simple Distillation (separate out solutions)
- Solution is heated.
- Lowest boiling point solution will evaporate first.
- Vapour is cooled, condenses and collected.
- Rest of the solution is left behind in the flask.
PRACTICAL: Fractional Distillation (separate a mixture of liquids)
- Put mixture in a flask, place a fractioning column on top.
- Heat. Different liquids have different boiling points so will evaporate at different times.
- Liquid with lowest boiling point will evaporate first.
- Collect liquid, then raise the temperature until the next one reaches the top.
What are 3 properties of metals?
- strong
- Good at conducting heat and electricity
- High boiling and melting points
Transition metals have 3 special properties, what are they?
- Can have more than 1 ion
- Colourful
- Good catalysts
What happens when Group 1 elements react with oxygen, water and chlorine?
Water: reacts vigorously, produces hydrogen gas and metal hydroxides.
Chlorine: reacts vigorously, heats to make chlorine salts.
Oxygen: forms a metal oxide
Group 7 elements: what are they, how do they share electrons and what ions do they form when bonded with metals?
Non-metals
Covalent bonding
1- ions
