atomic structure and the periodic table Flashcards
What is the relative charge and mass of protons, neutrons and electrons?
Protons: charge=+1, mass=1
Neutrons: charge=0, mass=1
Electron: charge=-1, mass=negligible
What do the mass number and the atomic number tell you?
The mass number is the total number of protons and neutrons in an atom and the atomic number is the number of protons ( also electrons)
What is an isotope?
An atom of the same element with the same number of protons and a different number of neutrons.
What is the relative atomic mass?
The average mass taking into account the different masses and abundances of all the isotopes that make up an element ( represented with a capital A with an r in the bottom right corner)
What is the formula for relative atomic mass?
relative atomic mass= Sum of (isotope abundance x isotope mass number) / sum of abundances of all the isotopes
What is an ion?
Ions are charged particles that have either lost electrons ( positive ions or cations) or gained electrons ( negative electrons or anions)
Which types of elements does ionic bonding take place between?
Ionic bonding takes place between a metal and a non metal.
What is ionic bonding?
Ionic bonding is where a metal gives one or more electrons to a non metal, making the metal a positive ion and the non metal a negative ion.
What is covalent bonding?
Covalent bonding is where one atom shares an electron with another atom, forming a covalent bond.
Which types of elements does covalent bonding take place between?
Non metals
How can you separate the different dyes in ink using chromatography?
- fill a beaker with a solvent made of water or ethanol
- draw a line on a sheet of filter paper and add a dot of ink to the line, placing the bottom of the paper in the solvent, ensuring the ink does not touch it
- Place a lid on the container to prevent evaporation and after the chromatogram has formed, allow it to dry.
What techniques can be used to separate solvents and solutes?
Crystallisation, distillation, filtration and evaporation
What is the difference between evaporation and crystallisation?
Crystallisation is used if the salt breaks down when heated so must be removed from the heat once the solvent has evaporated whereas with evaporation you can leave the mixture on the heat until only dry crystals are left.
Describe the simple distillation required practical
- Heat a solution in a flask with a thermometer in the lid and a condenser
- Allow the solution to cool, causing the evaporated liquid to condense into pure distilled water to be collected in a beaker
- Salt will be left in the flask
What is the difference between simple and fractional distillation?
Simple distillation can only be used to separate things with very different boiling points whereas fractional distillation can separate mixtures of multiple liquids with closer boiling points and is often used to separate crude oil.
Describe the process of fractional distillation
- Put your mixture in a flask with a fractionating column on top then heat it
- Evaporate the substance with the lowest boiling point first, using the thermometer to check, then collect it
- Continue to heat up your substance until the next one reaches the top.
What are the 5 atomic models and their creators?
- Solid sphere model, Dalton
- Plum pudding model, Thompson
- Nuclear model, Rutherford
- Planetary model, Bohr
- Today’s model, Chadwick
What was the plum pudding model?
Electrons scattered in a ball of positive charge.
Describe the alpha scattering experiment and the conclusions made from it
- Rutherford fired positive alpha particles at a sheet of gold foil
- Most particles went straight through the foil, showing that an atom is a lot of empty space
- some particles were deflected showing that they were being repelled by a positive nucleus.
Who discovered protons, electrons and neutrons?
Dalton discovered electrons, Rutherford discovered protons and Chadwick discovered neutrons.
What are the properties of metals?
strong, malleable, good conductors of heat and electricity, high boiling and melting points
What are some properties of transition metals?
They can form more than one ion, often colourful, can work as catalysts
What are the properties and trends of group 1 elements?
soft, low density, increase in reactivity as you go down the group, decrease melting and boiling points as you go down the group
What are the properties and trends of group 7 elements?
exist as diatomic pairs, have coloured vapours, become less reactive as you go down the group, increase melting and boiling points as you go down the group.
What are the properties and trends of group 8/0 elements?
stable, inert, colourless, increase in boiling point as you go down the group.
