Unit 1 - Atomic structure and the periodic table Flashcards
which model of the atom is a solid sphere
john daltons model of the atom
What is the plum pudding model
JJ thompson - the atom is overall positively charged with negatively charged electrons in it
what is the Rutherford model
made after gold foil experiment - some particles were scattered, some were deflected back, so the mass is concentrated in the nucleus
negative electrons orbit positive nucleus
what is the Bohr model
Electrons orbit the nucleus in shells
Who discovered the neutron?
James Chadwick
What is the top number of an element in the periodic table ?
The Mass number - the total number of protons and neutrons
What is the bottom number of an element in the periodic table ?
The Atomic number - the number of protons
How to find the amount of electrons ?
number of electrons is equal to the atomic number
How to find the number of neutrons
atomic mass - atomic number
What is an element ?
a substance made up of only one type of atom
What is a compound ?
a substance made up of two or more elements chemically bonded together
What is a mixture ?
consists of two or more substances that are not chemically bonded
How to balance equations?
You can only use large numbers, not small ones
what are half equations ?
An equation that shows what happens to one element in a chemical reaction
What is OIL RIG?
Oxidation Is Loss, Reduction Is Gain
(of electrons)
What is an ionic equation?
An equation that shows what happens to ions in a reaction
mixtures can be separated by_______ means
physical
What are the different means of separation?
Filtration, crystallisation, simple distillation, fractional distillation, chromatography
What does filtration do?
separates an insoluble solid from a liquid
What does crystallisation do?
separates a soluble substance from a solvent
What does simple distillation do?
separates a liquid and soluble solid from a solution
what does fractional distillation do?
separates two or more liquids that are miscible with one another
What does chromatography do?
separate substances that have different solubilities in a given solvent
What are the charges of sub atomic particles ?
proton : +1
Neutron: 0
Electron: -1
What is the relative mass of the subatomic particles?
proton: 1
neutron:1
electron: very small
How do you calculate the relative atomic mass?
((% of isotope A x mass of isotope A)+(% of isotope B x mass of isotope B)) / 100
How many electrons are in each shell?
2,8,8
How is the periodic table structured?
increasing atomic number
What is a group and what is a period?
group: vertical column
period: horizontal row
What does the group number tell us?
how many electrons are on the outer shell
What does the period number tell us?
the number of shells of electrons an atom has
Before the discovery of the subatomic particles, how did scientists arrange elements?
in order of their atomic weight
How did Mendeleev arrange the periodic table?
horizontally in order of relative atomic mass, left gaps for undiscovered elements
How did Mendeleev predict properties of undiscovered elements?
by using trends in groups
What limited the accuracy of Mendeleev’s periodic table?
isotopes were not known in Mendeleev’s time
What two types are elements split into?
Metals and non-metals
What do metals do in a reaction?
Lose electrons to become positive
What do non-metals do in a reaction?
form negative ions
What do non-metals do in a reaction?
Form negative ions
What does group number tell us about an element?
How many electrons it has in the outer shell
What does period number tell us about an element?
How many shells it has
What are the key differences between metals and non-metals?
Metals: conduct electricity, many react with acids,
Non-metals: don’t conduct electricity, many don’t react with acids
What is group 0 called?
Noble gasses
What are the characteristics of noble gases?
monatomic, non-flammable, colourless gasses, unreactive
What happens to boiling point of noble gasses as you go down the group?
Increases (but they all have low mtp and bpt)
What happens to the density of noble gasses as you go down the group?
They get more dense
What is group 1 called?
Alkali metals
What are the characteristics of alkali metals?
Soft metals, very reactive, low densities, low boiling point
What happens to alkali metals as you go down the group?
They get softer, more reactive
How does lithium react with water?
relatively slow reaction, fizzing can be seen and heard
How does sodium react with water?
sodium melts, moves about the surface of the water
How does potassium react with water?
More violent reaction than sodium, hydrogen burns with a lilac coloured flame, melts into a ball that moves about the surface of the water
How do the alkali metals react with oxygen?
(Lithium example)
4Li + O2 = 2Li2O
How do the alkali metals react with Chlorine?
(Sodium example)
2Na + Cl2 = 2NaCl
How do the alkali metals react with water?
metal + water = metal hydroxide + hydrogen
What is group 7 called?
The Halogens
Halogens are _____ molecules
diatomic
what are the Halogens appearance at room temperature
Fluorine - yellow gas
Chlorine - yellow / green gas - pale green in solution
Bromine - red/brown liquid - orange in solution
Iodine - purple/black solid - brown in solution
What happens to Halogens as you go down the group?
reactivity decreases, boiling point increases,
What are the characteristics of metals?
high melting points, high density, shiny, malleable, conductors of electricity / heat, ductile
What are some uses of transition metals?
catalysts, dyes / paints (transition metals form colourful compounds
