TOPIC C1- ATOMIC STRUCTURE AND THE PERIODIC TABLE Flashcards
atoms contain
-protons
-neutrons
-electrons
the nucleus of an atom
-in the middle of an atom
-contains protons and neutrons
-positive charge because of protons
-whole mass is concentrated
the electrons of an atom
-move around the nucleus in electron shells
-negatively charged and tiny
-volume determines the size
-virtually no mass
how are atoms neutral
-they have no charge
-because they have the same number of protons and electrons
what does the top number of a element tell you
-its mass number
(the number of protons and neutrons in the atom)
atomic number
bottom number
the number of neutrons, subtract the atomic number from the mass number
what is an element
a substance made up of atoms that all have the same number of protons in their nucleus
definiton of isotope
different forms of the same element that have the same number of protons but different numbers of neutrons
relative atomic mass formula
sum of (isotope abundace x isotope mass number)
DIVIDED BY——–
sum of abundance of all isotopes
atoms join together to make
compounds
symbol equations need to be
balanced
-same number of atoms on both sides
-can only put numbers infront of them
whats a compound
-substances formed from 2 or more elements
how can mixtures be seperated
by physical methods e.g filtration, crystallisation
explain paper chromatography
1.draw a line near the bottom of a sheet of filter paper USE PENCIL as theyre insoluble
2. add a spot of ink to the line and place the sheet in a beaker of solvent
3. solvent depends on whats been tested and some compounds dissolve well in water, but sometimes ethanol is needed
4. make sure ink isnt touching the solvent, prevents dissolving
5. lid ontop of container to stop the solvent
6. solvent seeps up the paper, carrying ink
7. each dye moves up the paper at different rates and spread out
8.
what does it mean in chromotography if any of the inks stay on the baseline
-they are insoluble
what do you use fractional distillation for
to seperate mixtures of liquids
in fractional distillation which liquid will evaporate first
-the one with the lowest boiling point
who described atoms as solid spheres in the 19th century
John Dalton
-they were different spheres made up the different elements
who created the theory of the plum pudding model
J J Thompson
-atom as a ball of positive charge with electrons stuck in it
-he concluded from experiments that atoms werent solid spheres
who proved the plum pudding model wrong
-Ernest Rutherfood
explain Rutherfords further ideas
-showed that the nucleus can be divided into smaller particles that have the same charge as hydrogen nucleus
-particles named protons
state the rules of electron shells
1st shell- 2electrons
2nd shell- 8electrons
3rd shell- 8electrons
-in most atoms the outer shell is not fill and this makes the atom want to react to fill it
whats the electronic structure of nitrogen
atomic number 7
whats the electronic structure of magnesium
atomic number 12
- 2,5
-2,8,2
explain Dmitiri Mendeleevs development of the periodic table
-in 1869 he took** 50**known elements and arranged them into his table of elements, with various gaps
-he put elements mainly in order of **atomic weight **
why did mendeleev leave gaps in his table
-to make sure elements with similar properties stayed in the same groups
-some gaps indicated the existence of undiscovered elements and allowed him to predict their properties
-when found they fit the pattern
what made mendeleevs decision right to not place elements in a strict order of atomic weight
the discovery of isotopes
how are elements laid out in the periodic table
-in order of increasing atomic (proton) number
means theres repeating patterns in the properties of elements
state where metals and non metals are found
-metals on the left
-non metals on the right
elements with similar properties form …
verticle columns are called
columns
groups
what does the group number tell you
how many electrons there are in the outer shell
except group 0, heliumm has 2in outer shell
-elements in the same group react in simalr ways
-G1 elements react vigorously as you go down
-G7 reacctivity decreases as you go down
properties of metals
-strong
-malleable
-good conductors of heat and electricity
-high boiling and melting points
properties of non metals
-dont have metallic bonding
-dull looking
-brittle
bad conductors of electricity
-low density
state what the following are known as
-G1 ELEMENTS
-G7 ELEMENTS
G0 ELEMENTS
1- alkali metals
7-halogens
0-noble gases j
stat
properties of group1 elements
-soft and have low density
TRENDS as you go down
-increasing reactivity
-low melting and boiling points
-high relative atomic mass
state what happens when group1 elements are put in water
+with chlroine
-react very vigorously
-tend to float and fizz
-produce hydrogen
-form hydroxides that dissolve in water to give alkaline solutions
-produces a salt, and metals react vigorously when heated in chlorine gas to form white salts
-as you go down the group, reactions get more vigorous
how do g1 metals react with oxygen
-react with oxygen to form a metal oxide
-lithium reacts to form lithium oxide
-potassium goes to potassium peroxide
the halogens are all —– with coloured vapours
* fluorine
* chlroine
* bromine
* iodine
-fluorine, very reactive, posinous yellow gas
* chlroine, fairly reactive, posinous green gas
* bromine, dense red-brown liquid
* iodine, dark grey solid/ purple vapour
state the trends in group 7
AS YOU GO DOWN
-become more/less reactive
-have higher/lower boiling and melting points
-have high/low relative mases
-become less reactive as its harder to gain an extra electron
-higher melting and boiling points
-high relative atomic mass
can halogens form molecular compounds, if so how
-they SHARE electrons via convalent bonding
-with other metals
-to achieve a full outer shell
what type of ionic bond do halogens form
1-ions called halides
group 0 characteristics
-8electrons in outershell
-colourless gases at room temp
-monatomic gases, not bonded
-non flammable
patterns in the properties
-boiling points increase as you move down
-increasing relative atomic mass
-increase in number of electrons in each atom leads to greater intermolecular forces
