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National 5 Chemistry
“Atomic Structure” homework
1.
The table shows the numbers of
protons,electrons and neutrons in four
particles, W, X, Y and Z.
Which pair of particles are isotopes?
2.
The table shows information about an ion.
The charge on the ion is
A
B
C
D
A
B
C
D
3.
1+
1–
2+
2–.
W and X
W and Y
X and Y
Y and Z
Glass is made from the chemical silica, SiO 2 , which is covalently bonded and has a melting point
of 1700 °C.
In the manufacture of glass, other chemicals can be added to alter the properties of the glass.
The element boron can be added to glass to make oven proof dishes.
(a)
Information about an atom of boron is given in the table below.
Use this information to write the nuclide notation for this atom of boron.
(1)
(b)
Atoms of boron exist which have the same number of protons but a different number of
neutrons from that shown in the table.
What name can be used to describe the different atoms of boron?
(1)
4.
The diagram represents the structure of an atom.
(a)
Fill in the missing information for:
(i)
(ii)
(b)
(1)
The element uranium has unstable atoms.
These atoms give out radiation and a new element is formed.
(i)
Complete the table to show the number of each type of particle in
234
90
Th.
(1)
(ii)
Radon is another element which gives out radiation.
State the atomic number of element X.
(1)
5.
A mass spectrometer is an instrument that can be used to measure the percentage of isotopes
in a sample of an element.
When a sample of chlorine is passed through a mass spectrometer the following graph is
obtained.
Each spike on the graph shows the presence of an isotope.
The relative atomic mass of an element can be calculated
using the formula:
(mass of isotope A x %) + (mass of isotope B x %)
100
The relative atomic mass of chlorine =
(35 x 75) + (37 x 25)
100
= 35.5
a)
The following graph was obtained for a sample of lithium.
(i)
How many isotopes are present in the sample of lithium?
(1)
(ii)
Using the information in the graph calculate the relative atomic mass of lithium.
(1)
(iii)
What is the mass number of the more common isotope in this sample of lithium?
(1)
b)
Complete the table to show the number of each type of particle in the ion,
7 Li
3
+
Particle
proton
electron
neutron
Number
(2)
Score:
/12