C4 Flashcards
With what piece of equipment can you see atoms
you can see atoms with an electron microscope
what does the nucleus of an atom contain
protons
neutrons
What are the properties of a proton
charge. +1
Mass 1
What are the properties of a neutron
charge 0
Mass. 1
what are the properties of an electron
charge -1
Mass. 0.0005
where is most of the mass of an atom concentrated
the nucleus of the atom contains the majority of mass despite the fact the nucleus only occupies a tiny amount of space
what determines the size of an atom
the volume of the electrons orbits
what charge does an atom have
an atom has no charge the number of protons in an atom are equal to the number of electrons in the atoms so the positive and negative charges counter balance to and hence the atom has no over all charge
what does an ion become if an electron is added or removed
if an atom looses an electron it looses a negatively charged particle so develops an overall positive charge , this is no longer an atom as it has a charge and is instead an ion.
if an atom gains an electron it will have attributed an additional negative force hence it will be a negative particle (a negative ion)
what is unique to each element
each different element has a unique proton number , atoms of the same element will have the same proton number but no two elements share the same proton number.
why do different elements have different properties
elements have different properties due to their atomic structure , for instance how many shells the atom has or how many electrons ,protons and neutrons are in the atom.
what can be seen if atoms are arranged in order of their proton numbers
when atoms are ordered in a sequence of proton number then there will be repeating patterns in the properties of the elements , in the modern day periodic table proton numbers increase as we move across rows.
why were we limited to the ways in which we could order the periodic table prior to the 1800’s
the only measurement possible was relative atomic mass , hence elements could only be put into order based on this measurment
what did dobreiner do in his attempts to fabricate the periodic table
Dobreiner made developments to the periodic table in 1828 . He put elements into triads which were groups of 3 elements. Within these triads elements had similar chemical properties. Another trend in the triads were that the relative atomic masses of the two elements that sat on the exterior of the middle element had relative atomic masses that equated when a mean was taken to approximately the relative atomic mass of the central element.
he put elements like:
lithium
sodium
potassium
into triads
what did Newlands do in his attempts to organise the periodic table
Newlands placed elements into octaves. groups of 8, the elements within the octave were ordered in sequence of relative atomic mass. Every 8th element in his octaves shared similar properties with one another.
Why did the scientific community oppose Newlands periodic table
Newlands method of ordering metals and seeing a pattern of every 8th element sharing similar properties broke down after the 3rd row. Hence his method of organisation only worked for the first 16 elements.
He was also apposed as his groups contained elements that did not have similar properties such as carbon and titanium.
His method of organisation also missed up metals and non metals like iron and oxygen.
Newlands also failed to leave gaps which meant elements that has not been discovered could not be implemented to coincide with the patterns upon discovery
In 1869 what did Dimitri Mendeleev do ?
In 1869 mendleeve took the 50 known elements of the time and arranged them into a table. Within this arrangement he left several gaps , he dd this to keep elements which similar chemical properties in the same group.
Mendeleev’s table put elements in order of relative atomic mass as Newlands had done.
in leaving gaps Mendleev was able to come to realise that there were elements that had yet to be discovered and it helped him to predict the properties of these elements
why was Mendeleev’s table accepted
Mendeleev’s table was accepted as when new elements where found which had properties that could place them in the gaps left by Mendeleeve it helped confirm his ideas.
plus his method of organisation seemed logical as it kept elements with similar properties in the same vertical groups.
in the box a element is stored in on the periodic table where is the relative atomic mass number stored
the relative atomic mass of an element is the number which appears apt the top of the box
THE BIGGER NUMBER OF THE TWO
in the box a element is stored in on the periodic table where is the proton number stored
the proton number is the number which appears beneath the symbol and title for the element
THE SMALLER NUMBER
How can you calculate how many neutrons an atom has ?
as the weight of electrons is negligible to work out the number of neutrons in an atom you simply subtract the proton number from the relative atomic mass. The result you are left with is the number of neutrons in the atom , normally it is about half of the relative atomic mass.
How are elements stored in the modern day periodic table
elements are ordered in oder of increasing proton number as you move across the rows , this means there are repeating patterns in the properties of elements
a vertical column in the periodic table is named ?
A group
a horizontal row in the periodic table is named
A period
what does the group number of an element tell you ?
the number of electron that are stored in the outer shell of the element
what does the period of the element tell you?
the period dictates how many shells the element has
on which side of the periodic tables are the metals found ?
left - remember because alkali metals are in the far left
what are elements found in group 1 referred to as
Alkali metals
as you move down the column of alkali metals how does reactivity change
the further you descend down the column of alkali metals the more reactive the elements become , this is because there are more shells that shelled the electrostatic force of the positive nucleus which holds onto the negative electron hence the electron can more easily be lost. It would be in the elements interest to loose the electron as it would mean it would be left with singularly full shells that remain.
the metals are hence more relative at the bottom of the alkali metals column as they can more easily loose an electron and losing or gaining a electron onsets a reaction
Name some qualities of alkali metals
Alkali metals are relatively light hence they generally float on the surface of water.
When alkali metals are cut their shiny surfaces quickly tarnish as the surface of the alkali metal reacts with the oxygen and moisture in the air.
Alkali metals are stored in oil so that oxygen does not instigate a reaction with the alkali metals.
