Atomic Structure And The Periodic Table Flashcards
what does the nucleus contain
the nucleus contains protons and neutrons
what charge is the nucleus
positive
what charge are electrons
electrons are negatively charged
what does atomic number tell you
protons
what does mass number tell you
protons and neutrons
what is an isotope
isotopes have the same number of protons but a different number of neutrons
what are compounds
compounds are substances formed from two or more elements
what was the first assumption atoms were and who made it?
John Dalton described atoms as solid spheres and that different spheres made up different elements.
who disagreed after experimenting that atoms weren’t solid spheres and what did he find out
JJ Thompson discovered the plum pudding model, In this model, the atom is a ball of positive charge with negative electrons embedded in it
who proved that the plum pudding model was wrong? and how did he prove this?
Ernest Rutherford proved the plum pudding model wrong by conducting the alpha particle scattering experiment.
Explain what led to the plum pudding model of the atom being replaced by the nuclear model of the atom.
alpha particle scattering experiment
alpha particles directed at gold foil
most alpha particles pass straight through which means most of atom is empty space
a few alpha particles deflected through large angles this means mass is concentrated at centre of atom and the nucleus is positively charged
who came up with the nuclear model and what was it
Nielhs Bohr proposed that electrons orbit the nucleus in fixed shells and that each shell is a fixed distance away from the nucleus
In the early 1800s what were elements arranged in?
Atomic Mass
Why did Mendeleev leave gaps in his table
to make sure that elements with similar properties stayed in the same group, also these gaps represented undiscovered elements which Mendeleev could predict the properties of.
what do group numbers represent
the charge
what do row numbers represent
how many shells the element has
what are the properties of metals 4 things
They’re strong
Malleable
They conduct heat and electricity
They have high melting and boiling points
What are the properties of transition metals 5 things
good conductors of heat and electricity very dense, strong and shiny they can form more than one ion they are coloured compounds They are good catalysts
what are group 1 metals known as
Alkali Metals
How many electrons do group 1 elements have in their outer shell THIS MAKES THEM…
one and this makes them very reactive and gives them similar properties
properties of alkali metals
They are soft and have a low density, low melting and boiling points
what are the trends as you go down group 1
- As you go down group 1 the more reactive the elements are this is because the electron on its outer shell is lost easily as the attraction between the electron and the nucleus decreases because the electron is further away from the nucleus
- Higher Relative Atomic Mass
- Lower melting and boiling points
What Compounds do alkali metals form with non metals
Ionic Compounds
Group 1 Metals reaction with Water
they react vigorously to produce hydrogen gas and metal hydroxides
the more reactive the metal the more violent the reaction
as you go down the group the more energy is given out by the reaction
Group 1 metals reaction with chlorine
Group 1 metals react vigorously when heated in chlorine gas to form white metal chloride salts
As you go down the group the more vigorous the reaction
Group 1 metals reaction with Oxygen
Group 1 metals react with oxygen to form an metal oxide
What are group 7 elements known as
Halogens
All the halogens have….
Coloured VApours
The coloured vapours (Group 7)
fluorine=
chlorine=
bromine=
iodine=
Fluorine- Yellow gas
Chlorine- dense green gas
Bromine- red brown liquid
Iodine- purple
What compounds can halogens form
Molecular Compounds
More reactive halogens will…..
displace less reactive ones
what is a displacement reaction
A displacement reaction can occur between a more reactive halogen and the salt of a less reactive one
the trends in group 7
as you go down group 7 it becomes less reactive as its harder to gain an extra electron because the outer shells further from the nucleus
as you go down they have higher melting and boiling points
as you go down they have higher relative atomic masses
what ions do the halogens form
1- ions
what are group 0 elements known as
they are known as noble gases
how many electrons are in the outer shell of a noble gas
they have a full outer shell of eight electrons
are noble gases reactive
no they hardly react at all
what do noble gases exist as
noble gases exist as monatomic gases- single atoms not bonded to each other
what are noble gases at room temperature
they are colourless gases at room temperatures
the trends in group 0
the boiling points of noble gases increase as you move down the group this is due to the increase in the number of electrons in each atom leading to the greater intermolecular forces between them which they need to overcome
the relative atomic mass increases as you go down
what does a pure substance consist of
a pure substance consists only of one element or one compound
who led to the discovery of protons
james chadwick
an element has three different isotopes what do they all have in similar
all have the same chemical properties
what is an isotope named after
its element and its mass number
how do you work out the atomic mass of an element
change percentage abundance of isotope to a decimal and times it by mass number
once you’ve done that add both of them together
what do halogens exist as
simple molecules
what are halogens joined together by
a covalent bond
what happens when an halogen reacts with a halide
produces a hydrogen halide
what are hydrogen halides
hydrogen halides are gases at room temperature. They dissolve in water to produce acidic solutions.
halogens different reactions with hydrogen
Fluorine
Explodes at room temperature and in the dark, forming hydrogen fluoride
Chlorine
Explodes with a flame or in sunlight, forming hydrogen chloride
Bromine
Vigorous reaction when warmed with hydrogen, forming hydrogen bromide
Iodine
Very slow reaction when heated strongly, forming some hydrogen iodide
chadwicks work on the atom led to a better understanding of isotopes explain hows his work led to this understanding
chadwich provided the evidence for neutrons
this was helpful as isotopes have the same number of protons but with a different number of neutrons
describe a method to find the poition of an unknown metal in this reactivity series
add all metals to an acid
measure the temperature change or compare rate of reaction
place metals in order of temp change or rate of reaction
to give valid results you should use the same volume of acid
