atomic structure Flashcards
What is an atom? ★
The smallest part of an element that can exist.
What is an element? ★
A substance made up of only one type of atom.
What is a compound? ★
[examples included]
Two or more different elements chemically bonded together in a fixed proportion.
e.g., water, soap, baking soda, sugar etc.
What is a mixture? ★
[examples included]
Two or more elements/compounds not chemically combined together.
e.g., sea water, air, ink, crude oil etc.
What is shown in a chemical equation? ★
● The reactants (what you start with).
● The products (the new substance).
What does it mean to have a balanced symbol equation? ★
There’s the same number of each atom on both sides of the equation.
What’s the law of conservation of mass? ★
Total mass of the products formed in a reaction is equal to that of the reactants.
What are the state symbols? ★
● s = Solid.
● ʟ = Liquid.
● g = Gas.
● aq = Aqueous solution: substances dissolved in water.
What are examples of processes that can separate mixtures? (5) ★
● Filtration
● Crystallisation
● Simple distillation
● Fractional distillation
● Chromatography
What is filtration? ★
[include the process]
The physical process which separates insoluble solids from a solution/liquid.
● Insoluble particle remain on filter paper, in filter funnel, as a residue.
What is crystallisation? ★
[include the process]
The physical process which separates soluble solids from a solution using evaporation.
● Gently heat the solution to remove water - this leaves the crystals behind.
What is simple distillation? ★
[include the process]
The physical process which separates soluble solids from a solution, if you want to keep the liquid.
● Solution boiled to evaporate solvent
● Vapour is cooled so it condenses
● Liquid is collected
What’s fractional distillation? ★
The physical process which separates miscible liquids that have different boiling points.
What is chromatography? ★
[include process + reason]
The physical process which separates mixtures of substances by dissolving them in a solvent.
● The mixtures of substances move up a piece of chromatographic paper.
● They separate as they have different solubilities in the solvent used.
What is a miscible? ★
[examples included]
Liquids that dissolve in each other, mixing completely.
e.g., ethanol + water, lemonade, wine etc.
What did the plum pudding model suggest? ★
[include person]
The atom is a ball of positive charge with negative electrons embedded randomly in it.
– JJ Thompson
What did the alpha particle scattering experiment conclude? ★
[include person]
● Mass of an atom was concentrated at the centre (nucleus)
● Nucleus was charged - contained dense positively charged protons.
● There were empty spaces.
● Electrons orbited the nucleus.
– Ernest Rutherford
What is the last particle to be discovered?
[include reason]
Neutrons as they have no charge.
What are the three subatomic particles? ★
Protons, neutrons, electrons.
What is the relative charge of the subatomic particles? ★
● Protons = 1+.
● Neutrons = 0.
● Electrons = 1-.
Which subatomic particles are (mostly) equal in numbers? ★
Protons and electrons.
What is the charge of atoms? ★
[include reason]
It has no overall electrical charge because the number of protons = number of electrons, cancelling the charge.
What is the atomic number? ★
Number of protons in an atom of an element.
What is different between elements? ★
Their number of protons.
What is the size of an atom? ★
[include radius]
Very small.
approximate radius = 0.1nm (1x10-10m).
What is the radius of a nucleus? ★
Radius of nucleus is less than 1/10,000 of the atom.
approximate radius = 1x10-14m.
Where is most of the mass of an atom located?
Nucleus.
What is the relative mass of the subatomic particles? ★
● Proton = 1
● Neutron = 1
● Electron = nearly 0 (1/2000)
What is an isotope? ★
Atom of the same element with different numbers of neutrons.
How do properties of isotopes differ?
● Chemical properties are identical as they have the same number of electrons in their outer shell.
● Physical properties can differ due to different numbers of neutrons.
What is the atomic mass number? ★
Total sum of protons and neutrons in an atom of an element.
What is an ion? ★
An atom of an element with an overall charge which are formed when atoms gain or lose electrons.
What ions do metals/non-metals react to form?
● Metals form positive ions.
● Non-metals form negative ions.
What ions do metals/non-metals react to form?
● Metals form positive ions.
● Non-metals form negative ions.
Where are electrons arranged in an atom? ★
In energy levels or shells.
How many electrons can each shell hold? ★
● 1st shell can hold 2 electrons.
● 2nd and 3rd shell can hold 8 electrons.
● 4th shell can hold 18 electrons.
What determines the way an element reacts?
Amount of electrons in the outermost shell.
What is shown in the electronic structure? ★
[example included]
It notes the number of electrons in each shell, separated by commas.
e.g. sodium = 11 electrons so… 2,8,1
What is a molecule? ★
Two or more elements held together by a chemical bond (whether the same or different).
