Atomic Structure 2.1.1 Flashcards
What did Atomos do and in what year
History of the atom
500 BC- Atomos= discovered atoms are building blocks of all matter + are indivisible
What did Jhon Dalton discover and in what year
History of the Atom
1800+, Dalton= Atoms are tiny particles that make up an element
What did JJ Thompson discover and what year
History of the Atom
1897-1906=JJ Thompson- Plum Pudding Model- sea of delocalised electrons in a ball of positive charge
What did Rutherford discover and in what year
History of the Atom
1909-1911= Rutherford- Gold foil experiment- the atom is mostly empty space with a tiny dense positively charged nucleus
As a results of Rutherfords experiment what was the next significant discovery about the history of the atom and how was this shown
History of an atom
The Nuclear Model- mass of an atom is mostly concentrated in a centre with positive nucleus
Who came after the Nuclear model and what did they discover, and in what years
What was discoevered after this by scientists
History of the atom
1913-1920= Neils Bohr– found electrons orbit in energy levels or shells
Then discovery of positively charged protons was done by scientists later on
What did James Chadwick do and in what years
Histroy of the atom
1932= James Chadwick– discovered nucleus contained neutral parts also known as neutrons
What did the final version of the Nuclear model state
Histroy of the atom
Atoms have no overall charge as protons and electrons cancel each other out
List all key events in order of the history of the atom
History of the Atom
500BC= Atomos
1800+= Jhon Dalton
1897-1906=JJ Thompson
1909-1911= Rutherford
The Nuclear Model
1913-1920=Neils Bohr
Discovery of postively charged protons
1932= James Chadwick
Final version of the Nuclear model
What are atoms of elements represented by
Atomic symbol
What does the atomic number show and is it the smaller or bigger number
-Smaller number
-tells you the number of protons and electrons
What does the Relative atomic mass show and is it the smaller or bigger number
-Bigger number
-Relative atomic mass -atomic number= Number of neutrons present
Draw out an atom and label it
Look in Chemistry book
What is the relative charge and relative mass of a proton
Relative charge of a proton= 1+
Relative mass of a proton= 1
What is the relative mass and the relative charge of a neutron
Relative mass of a neutron= 1
Relative charge of a neutron= 0
What is the relative mass and the relative charge of an electron
Relative charge of an electron= 1-
Relative mass of an electron= 1/1836
Draw out the table of protons, neutrons and electrons and their relative atomic charges and relative masses
Chemistry book
What are the forces which are present within an atom
- Same number of protons and electrons- meanning the charges cancel out so there is no overall charge on atom
- There is always a positive charge in the nucleus because of the positive protons
How would a Li atom differ from a Li + ion
Lithium ion= Stable, has an overall charge (+1)-has lost an electron so is a cation
Lithium atom= unstable, needs to loose an electron, has no overall charge, protons+ neutrons cancel eachother out
Which particles are sometimes called nuclides or nucleons
Neutrons and protons
The mass of an electron is…
negligible
What is an ion
-When an atom loses or gains electrons
-A charged atom
What is an isotope
An atom of the same element with the same number of protons but different number of neutrons
What is an anion
Negative ions formed when an atom has gained electrons
What is a cation
Positive ions formed when atoms have lost electrons
What is the difference between a Chlorine atom, Chloride ion and Chloride isotope
Chemistry book
What is the relative isotopic mass
The mass of an atom of an isotope compared with 1/12th the mass of an atom of Carbon 12
What is the relative atomic mass
The weighted mean mass of an atom of an element compared to 1/12th the mass of an atom of Carbon 12
What does the relative atomic mass have to be stated to
always to 1dp unless otherwise stated
What always has to be stated to 1 dp unless otherwise stated
Relative atomic mass
What is the Relative molecular mass
the average mass of a molecule compared to 1/12th the mass of an atom of Carbon 12
How do you find out the relative atomic mass of an element
R.A.M = (isotopic mass of a x % abundance of a )+ (isotopic mass of b x % abundance of b) /
100
Write out the 2 formulas to find out the relative atomic mass of an element
Chemistry book
Why don’t different isotopes of an element react in the same way
Because they have the same number of protons and electrons. Neutrons have no effect on reactions of an element.
How can an isotope differ from an element in terms of its properties
Physical properties- with higher mass, isotopes of an element have a higher melting point, boiling point and density, but chemical reactions are the same
What are the units of relative molecular mass and relative formula mass
They have no units
What is mass spectrometry used for
-spectra can be used to provide structural information
-can be used to identify unknown compounds
-can help to determine the relative abundance of each isotope of an element
-can help compare masses of elements relative to one another and work out the relative molecular mass of compounds
What is the equation for mass spectrometry
%abundance=peak height/total height of all peaks multiplied by 100
Equation to find percentage abundance in mass spectrometry
Chemistry book
What is a mass spectra produced from and what does it show
Mass spectra is produced from mass spectrometer and shows a trace of mass number vs abundance (peak height)
What is the importance of C12 isotope
We compare masses of atoms on a C12 scale where one atom of the isotope carbon 12 weighs exactly 12
On a mass spectrometer what is the peak height also known as
Abundance of that specific isotope
What does the number of peaks tell us in mass spectrometry
Number of isotopes an element has
What does the mass of each peak tell us in mass spectrometry
The number of different isotopes
What does the height of each peak tell us in mass spectrometry
The isotopic abundance of each isotope
How do you calculate the relative molecular / formula mass?
Add the relative atomic masses of all the atoms in the molecule
How does a mass spectrometer work?
1)A sample is placed into mass spectrometer
2)sample is then vaporized and ionized= atoms/ molecules are bombarded with a stream of electrons, collision will result in electron being knocked off particle resulting in a + ion (most ions will have +1 charge)
3) These ions are then accelerated= positively charged ions repel from the ionization chamber and pass through negatively charged slits which focus + accelerate ions onto a beam
4) the stream of positively charged ions are then deflected by magnetic field= amount of ions deflected depends on m/z (mass to charge) ratio- (heavier ions move slowly therefore are difficult to deflect than lighter ions) (ions with a greater charge- more than 1+ will be deflected more), ions of each isotope are separated
5) ion is detected on the mass spectra=ion hits detector and charge is neutralized, this generates electrical current which is proportional to the abundance of the ion
6) these are sent to computer for analyses
7) for most ions the charge is 1 thus m/z ratio is simply the molecular mass of the ion
Draw out the process in which different isotopes are recognized and separated
Mass spectrometry diagram in chemistry notes alongside the method of how it works and what happens during each stage
What does m/z mean in mass spectrometry and explain why we can use this and abundance to calculate Relative Atomic mass
m/z means mass : charge ratio of an ion
-in mass spectrometry a molecular ion is formed and always has charge of 1+
X—–> X+ PLUS E-
Molecular ion= x+ PLUS e-
-mass/1 = the same mass
-so R.A.M. is the same as its isotope of the element
- so m/z is the same as the relative mass of the isotope- isotopic mass
You can calculate Relative atomic mass by using the equation and finding the mean average of all isotopes of the element:
(% abundance A of isotope * isotopic mass A )+ (% abundance of isotope B * isotopic mass of B) /100
Because relative atomic mass is the same as the isotopic mass you can use this equation.
Its just a fact you have to learn.
What is relative formula mass
RFM= The mass of the formula relative to 1/12th the mass of an atom of C-12
What is the difference between relative formula mass and relative molecular mass
RFM= mostly used for Giant ionic compounds e.g. salts
Mr= mostly used for simple covalent molecules
How do you calculate the relative molecular /formula mass
The relative molecular mass of a molecule is calculated by adding the relative atomic masses of all the atoms in the molecule
e.g. Molecular mass of C6H1206
First we find the atomic masses of each atom in the compound
C-12
H-1
O-16
Now we multiple by how many there are of each atom
126= 72
112=12
16*6=96
Add them up
72+12+96= 180
Relative molecular mass of glucose= 180
What does the m/z tell us on a graph from mass spectrometry
The number of different isotopes and their isotopic masses
Why did the Plum Pudding model become ‘not good enough’
Because it contradicted the gold foil experiment by Rutherford in 1909. This was when alpha particles were fired at a thin sheet of gold, according to the PPM the alpha particles should have passed straight through ‘pudding’ of positive charge. However Rutherford observed the particles instead deflected at large angles and even bounced back.
This suggested that the positive charge, and most of the mass of the atom was concentrated in a small central nucleus, contradicting the plum pudding model.
Do Page 9 question 4 and 5
in Atomic Structure and Isotopes booklet
Do page 10 and 11 aswell
Do page 5 of Atomic Structure Booklet
Complete the table at the top
What happens to subatomic particles when atoms form: 1)Negative ions
2)Positive ions
1)Form a positive charge
2)Form a negative charge
Name the atomic particle which has no charge
neutrons
Name the atomic particle which has the lowest mass
Electrons
Name the 2 atomic particles found in the nucleus
Protons+ Neutrons
Where are the electrons found in an atom
On the energy shells/ levels, orbiting around the nucleus
Do question 2 and 3 on page 15 of atomic structure booklet
Might aswell do page 16 whilst you are at it.
What is the standard isotope to which the masses of all atoms are compared
Carbon 12
Scan the Quizlet QR code and do questions
It is on the front page of the Atomic Structure and Isotopes Booklet
Scan QR code on page 5 of atomic structure booklet at the bottom of the page and attempt all questions
In Kerboodle Textbook Year 1 Chemistry do summary questions on page 11
In Kerboodle Textbook Year 1 Chemistry do summary questions on page 14
In Kerboodle Textbook Year 1 Chemistry do practice questions on page 19
Calculate the relative atomic mass of tellurium from the following abundance data:
124-Te relative abundance 2; 126-Te relative abundance 4; 128-Te relative abundance 7;
130-Te relative abundance 6
R.A.M = [(124x2) + (126x4) + (128x7) + (130x6)] /
19
= 127.8
Copper has two isotopes 63-Cu and 65-Cu. The relative atomic mass of copper is 63.5.
Calculate the percentage abundances of these two isotopes.
63.55 = yx63 + (1-y)x65
63.55 = 63y +65 -65y
63.55 = 65 -2y
2y = 1.45
y = 0.725
%abundance 63-Cu =72.5% %abundance 65-Cu = 27.5%
Do Atomic Structure and isotopes Quiz 1
Should be in main Chemistry Folder by Atomic structure Booklet and C3 booklet in a polly pocket
Do Atomic Structure and isotopes Quiz 2
Should be in main Chemistry Folder by Atomic structure Booklet and C3 booklet in a polly pocket
Do Questions 1, 2, 3 in Atomic Structure C3 Booklet
Should be in main Chem folder by Atomic Structure booklet
Do Questions 4, 5, 6 in Atomic Structure C3 Booklet
Should be in main Chem folder by Atomic Structure booklet
Do Questions 7, 8 and 9 in Atomic Structure C3 Booklet
Should be in main Chem folder by Atomic Structure booklet
Take out Atomic Structure, Isotopes and Formulae Test and do questions you have got wrong