LLG
Paris–Abu Dhabi
Advanced Math and Science Pilot Class
School year 2014-2015
Chap 1 – Chemistry
Assignments 1
DATA:
Mass (kg)
Unit of charge
Charge ( C =
Coulomb)
Electron
9.10910-31
-1
Proton
1.672910-27
+1
Neutron
1.674910-27
0
-1.60210-19
+ 1.60210-19
0
1- Draw the Bohr model for a Lithium atom.
2- a) Give the values of the mass of the different particles building up an atom using 3
significant figures (3 s.f).
b) Compare the mass of a proton with the mass of a neutron. Justify the use of a single
mass: m(nucleon) = 1.6710-27 kg to calculate the mass of the nucleus.
c) Compare the mass of a nucleon with the mass of an electron. Conclude.
3- From the data read on the document
beside, find how far would the outermost
electron of an atom be if the nucleus was
enlarged to a ping pong ball (4 cm).
Explain why it is said that an atom is
mostly made of empty space….
4- What is the standard notation for the
atoms of Potassium 39, Sodium 23, Nitrogen 14, Oxygen 16, Calcium 40, Iron 56,
Copper 64.
5- Give an isotope ( use standard notation) of each of the atoms written in 46- a) Calculate, using the data in the table, the mass of the atom of potassium 39, by
adding all the particles it is made of.
b) Calculate the mass of the nucleus of potassium 39. Compare to the previous value.
What do you notice? What does it mean?
7- What is the charge carried by the nucleus of the atom of potassium 39? What is the
charge carried by the electrons? (give the result in charge unit)
8- Give the composition of the atom of gold 197, its mass and the charge of its nucleus.
9- Identifying an unknown atom named: X.
A sample made of 3.741023 atoms X has a mass m (sample) = 10.0 g:
a) Calculate the mass of one atom X : m(one atom X)
b) Deduce the mass number A of atom X.
The atomic number Z of atom X is half of its mass number A:
c) Identify atom X and give its standard notation.
d) What is the number of electrons in atom X?
10- The nucleus of Atom X has an electric charge Q(nucleus) = + 2.7210-18 C.
a) Deduce the atomic number Z of atom X and identify it.
b) Knowing that the nucleus of the atom has 18 neutrons, give its standard notation.
LLG
Paris–Abu Dhabi
Advanced Math and Science Pilot Class
School year 2014-2015
Chap 1 – Chemistry
a)
b)
c)
d)
e)
f)
11- We study the ion of copper Cu2+ with a mass number of 63.
Give the standard notation of this ion.
Has the copper ion gained or lost electrons compare to the atom of copper?
Give the composition of the copper ion Cu2+.
What is the charge of the nucleus in the Cu2+ ion? ( in charge unit)
What is the charge of all the electrons? (in charge unit also)
Find the value of the charge of the ion by adding the charge of the nucleus and the total
charge carried by the electron, check that it is OK with its formula.
a)
b)
c)
d)
12- We study the ion of sulfur S2- with a mass number of 32.
Give the standard notation of this ion.
Has the sulfur ion gained or lost electrons compare to the atom of sulfur?
Give the composition of the sulfur ion S2-.
By following the work done previously, make a charge statement of the nucleus, the
electrons and the ion.
13- The atomic number of silicon is 14 and its number of neutrons varies from 14 to 17.
a) Write the standard notation of all the possible atoms for this element. How are they called?
b) How many electrons have the isotopes of this chemical element? Why?
c) Do isotopes have the same charge? (Specify the situation for nucleus and electrons)?
14- One considers zinc’s nucleus represented by 3064Zn and 3068Zn .
a) How are these nucleuses called? Justify your answer.
b) Calculate the mass of each nucleus and conclude.
c) A zinc atom can lose two electrons. What is it changed to?
15- A cycle for the iron element.
Iron (in powder) and sulphur react violently when heated. They are changed to a new
compound: iron sulphide whose formula is: FeS
a) Fill the following diagram showing the transformation that occurred to element iron:
When introducing an iron sulphide fragment into a test tube filled with hydrochloric acid, a
gaseous emission of hydrogen sulphide (which smells like rotted eggs) occurs and the liquid
takes a greenish colour characteristic of the ion iron: Fe2+(II).
b) Make for this transformation a diagram similar to the one done in a).
In the previous test tube (containing now some iron ions), a zinc plate is introduced. The
immersed part of the plate is soon covered by a metal iron deposit.
c) Represent the complete cycle carried out by the iron element in this exercise. What do you
notice?
16- Fill the table