Download Atomic Structure Lesson 5 – Relative Atomic Mass and more Exercises Chemistry in PDF only on Docsity!
Nat 5 : Unit 1 – Chemical Changes and Structure
Key area – Atomic Structure
Lesson 5 – Relative Atomic Mass
By the end of the lesson, you should be able to …
- Explain that the Relative Atomic Mass (RAM) is the average mass of the
isotopes present, taking into account their relative proportions.
- Given data, identify the most or least abundant isotope
- Calculate the Relative Atomic Mass using a given formula.
You will have been successful in this lesson if you:
1. Read and learn the notes given 2. Watch the links provided 3. Complete the self-checks provided 4. Complete homework 8 questions 1,2 &3 (Attached at the end of the
document) for
Friday 22
nd
January to be submitted via MS teams or glow email
to your class teacher.
If you have any questions about the content of this lesson, you should ask your
class teacher either through your class MS team or via email. MS Teams will be
monitored throughout the week by a chemistry teacher. If you need help or
clarification with either the task or the content of the lesson, just ask.
You may wish to revise the following to help you understand this lesson:
Learning Outcomes
Success Criteria
Links to Prior Knowledge
Relative atomic mass
Actual masses of atoms are far too small for convenient use. It takes
six million million million million hydrogen atoms, for example, to
weigh just 10 g. Because of this, a relative scale is used based on one
atom of carbon-12 given a mass of 12 atomic mass units (amu) exactly.
The effect of this is that we can treat the mass number of an atom as
being a good approximation to the mass of an atom in atomic mass
units. Information from a mass spectrometer for the element Bromine
is shown
What to do
Watch the power point slide.
Copy the notes (or print and stick into your note book). Follow the
instructions to complete diagrams or tables. Remember to watch the
video links
WATCH - Mass Spectrometry - Chemical analysis is inte... - ClickView
YouTube – R.A.M. https://youtu.be/8AKalCm3Ros
The relative atomic masses of most elements are not whole numbers
because of the existence of isotopes.
Chlorine, for instance, has two isotopes
It might seem that the average mass (relative atomic mass) of chlorine
should be 36. This is not so, because this is where the abundance of
each isotope is important
75% of all chlorine atoms have a mass of 35.
Only 25 % of the atoms have a mass of 37.
The average is closer to 35 than to 37. In fact, the relative atomic
mass of chlorine is 35.5.
CLick on the link below to access the power
point lesson on isotopes
Remember to add to your notes by copying or
printing out and sticking in.
BBC bitesize Relative atomic mass - Atomic number, mass number and isotopes - GCSE Chemistry
(Single Science) Revision - Other - BBC Bitesize
Watch How To Calculate Relative Atomic Mass | Chemical Calculations | Chemistry | FuseSchool -
YouTube
Evans2 chem web: https://www.evans2chemweb.co.uk/login/index.php#
Username: snhs password: giffnock
Select any teacher revision material Nat5 chemistry Unit 1 :chemical
changes and structure relative atomic mas
Self Check 14
1. Two types of neon atom exist, one has a mass number of 20, the
other has a mass number of 22.
a) Write the symbol for each atom showing the atomic and mass
numbers.
b) Calculate the number of protons, neutrons, and electrons for the
neon atom with a mass of 22.
c) Give the electron arrangement of a neon atom.
d) What name is given to atoms like the neon atoms described
above.
2. Chlorine has two isotopes, one with a mass of 35 and one with a
mass of 37.The relative atomic mass of chlorine is 35·5.Which atom
of chlorine is more common?
3. Atom A has an atomic number of 93 and a mass number of 239.
Atom B has an atomic number of 93 and a mass number of 2 41.
a) How many protons are present in atom A?
b) How many neutrons are present in atom B?
c) Are A and B isotopes? Explain your answer.
Further Work
Check your understanding – Answers the questions below in you
class jotter
Isotopes/Relative Atomic Mass 8
- Atom A has an atomic number of 93 and a mass number of 239.
Atom B has an atomic number of 94 and a mass number of 239.
Are A and B isotopes? Explain your answer.
- Two types of neon atom exist, one has a mass number of 20, the
other has a mass number of 22.
(a) Write the symbol for each atom showing the atomic and mass
numbers.
(b) Calculate the number of protons, neutrons, and electrons for
the neon atom with a mass of 22.
(c) Give the electron arrangement of a neon atom.
(d) What name is given to atoms like the neon atoms described
above.
(e) Explain why you cannot calculate the relative atomic mass of
neon from the above information.
- A sample of nitrogen was found to contain equal amounts of two
isotopes. One isotope has mass number 14 and the other has mass
number 15. What is the relative atomic mass of this sample of
nitrogen?
Read through BBC bitesize Attempt the quiz once you have read
through all the pages.
https://www.bbc.co.uk/bitesize/guides/zw2gpbk/revision/
Check your knowledge with this online test Atoms, isotopes and ions -
AQA test questions - AQA Trilogy - GCSE Combined Science Revision - BBC
Bitesize
HOMEWORK
Extra work
